hi

i thought it would be useful to document my experiences of running bubblers, including building them from scratch.

firstly, i should make it clear i dont consider myself an expert and if anyone wants to chip in with their own experiences or add to what i have written here, please feel free.

so far, i have done a couple of grows with bubblers and have kept mums for over a year also in dwc and what may be useful to the reader here is that ive made probably every mistake possible along the way, so im going to try to include all the gotcha's that can screw your grow up in dwc.

i will start with how to build a bubbler and then proceed on to how to run them.

i will not be talking about the lucas formula as i have no experience of it. for info on running bubblers using the lucas formula, and RO water, i would suggest talking to cheese farmer and checking out cannabisworld.com. i could be wrong, but i dont believe anyone here at uk420 is running bubblers with RO (reverse osmosis) water and the lucas formula. if someone is, please feel free to discuss it here.

so, to start, let me talk about constructing a bubbler, firstly what you will need...

tubs!

i have tried several types of tubs now but all from the same brand, just different sizes. the size of the tub you use depends on the number of plants you wish to grow in that bubbler, but i have found reservoir management easier in bigger tubs.

i have 12L, 30L and 50L tubs (the tubs are bigger than that, thats how much liquid i put in the diff size tubs, for instane, the 50L tub is actually about 70L in size but holds 50L of res when the hanging net pots are taken into consideration as you dont fill bubblers up to the top!!)

another thing to be aware of is that if you use a big bubbler, be sure to use a strong tub as the walls will warp... the bubbles i use are pretty heavy duty buggers, but they do warp slightly at the sides so i use tape to make sure the side walls are firmly attached to the lid, will talk more about that later. the point being you dont want ANY light getting into the bubbler, it must be completely covered for the roots to be healthy.

also, if youre working with big bubblers, you can try out different lid combinations by cutting different number of pot holes in to the lid to grow 2, 4 or whatever number of plants you need. here you can see i have an 8 plant and 2 plant lid, and a lid with no pot holes.

the 8 plant lids are really for SOGS otherwise overcrowding will be a problem with that lid. 2 plant lids, or 4 plants used in an 8 plant lid is more suitable for the bigger tubs you can see in the pic.

talking of pics...

you will need to aeriate the reservoir well, and you have several options to do this, namely some type of airstone or soaker hose.

here i will only be talking about airstones as thats all ive used, but i firmly believe from listening to other hydro growers that soaker hose is the way to go for more air with less pressure.

i would suggest if you are using big bubblers with multiple plants to get some 4mm micro hose instead of using airstones - thats an upgrade i plan to do later this year.

for smaller bubblers airstones are fine, but here you will see how i have used airstones for larger bubblers - its perfectly possibly to do, well, so long as you use good enough air pumps (see next post about airpumps).

in these pics you can see different types of airstones - ive tried them all!! and for me, by far the best are the Aqua Fizz 12" toblerone airstones because they give off the most amount of bubbles...

some airstones are really shit! in fact, most of the airstones you can see in these pics i dont use anymore cos theyre rubbish. i try and stick to just the toblerone ones.

you will need some of these, airline splitters and airline. airpumps, airline, and splitters can all be bought from aquarium shops.

here you can see lots of 3 way splitters - DONT USE THESE - stick to putting two airstones on each airline, or 4, or 8, depending on the power of the airpump, ive found even number of airstones work better than 3 airstones per airline...

or to be more precise yet, i have found that a standard 150L p/h airpump, dual outlet, can run 4 x 12" airstones, it takes the pressure of 75L p/h to run one 12" airstone, so 150L p/h coming out of two outlets can run FOUR airstones.

if you use a compressor (discussed later) you can use many more airstones, but the pressure of the air must be taken into consideration when using lots of airstones.

you will need these tools to make a bubbler...

the drill for drilling holes and the saw for making the holes in the lid for the net pots. if you can find a big enough round saw, which i couldnt, you could use a round saw to make the holes in the lid, but the netpots im using are 100mm at the base and the biggest round saw i could find was 100mm which was just not quite big enough...

sawing the holes in the lid is the pain in the arse job, the hardest bit of making a bubbler, so if you can find smaller net pots and a big enough round saw, go for it!

i strongly suggest installing a thermometer in your tubs.

for a bubbler, the optimum temps are 68 degs F to 78 degs F. for a bubbler cloner, the optimum is 78 F to about 85F, a warmer res for cloning is required.

below 60 degs F and the roots will die, so an aquarium heater will be needed in the colder months.

above about 80 degs F for a bubbler is too high too, temps are v. important!

infact, i have decided to stop growing mums in bubblers because i cant keep the temps low enough in the summer so im in the transition of converting my mum box to soil andwill only grow in bubblers when its not blazing hot.

here in switzerland, it gets very hot in summer and i just cant see how i could keep the res temps low enough... thats probably why hydro growers here prefer to use drippers where the reservoir can be kept OUTSIDE of the growroom, and hence cooler.

in england it might not be such a problem.

aeriation of the res is v. important in bubblers so using the right airpump is important.

here you can see i have a selection of airpumps...

theres a 1 outlet 150L p/h airpump which can run 2 x 12" airstones, not very useful really, the double outlet airpumps 150L p/h are fine for 4 airstones, but ideally, in my size of tub, i need 8 airstones so 2 x 150L p/h pumps is needed, or a compressor!! (also photographed)

i have worked out that that compressor can run 48 x 12" airstones with all the airstones working properly. above that the air pressure is too low, and airstones stop working.

the only problem with the compressor is its noisey as fuck! similar sort of noise to an extractor fan, so hanging it from bungees in the growroom helps a lot with this noise.

lots of bubbles!

you need to drill a hole or two in the side of the tub, NOT in the lid!

depending on how many air inlines you need for the number of airstones, you might need 1 or 2 holes... ive been testing with 16 airstones!! 2 banks of 8 airstones, each bank needing an airline from the compressor - which is powerful enough to run 2 banks of 8 airstones on 2 airlines, but this would NOT be possible with a standard airpump.

here you can see three holes.

2 at the top for airlines and
1 at the bottom where i install some tubing so i can see the level of the res - this is totally optional and not really needed tbh.

make sure you drill the airline holes near the top of the tub so when the res is inside it does NOT reach the airline hole and leak out...

make the holes in the lid a bit bigger than the base of the netpot, but smaller that the top part, so that when the netpot is installed in the hole it fits really well, tightly, and snugly in the hole with about 80% of the netpot in the hole.

if the lid is too low, you risk a heavy flowering plant being too heavy and causiung the net pot to fall through - ive not done this personally but its something to consider.

i measure the diameter of the top of the pot and the bottom of the pot and make the hole a bit smaller than the top part of the pot, which is biggest.

pics for clarification...

when you install the airstones, you dont want them too move about, and to be placed ideally under the plants, so the bubbles are in contact with the roots.

some people glue the stones to the tubs, i dont like this because it makes cleaning harder and also replacing the airstones would be a pain, so instead, i build a rack of airstones, made up in pairs, and then supply the necessary air pressure to drive that number of stones.

for instance, if i have 1 rack of 8 airstones, i can drive that with either an airline from the compressor, or 2 x 150L p/h pumps and 2 airlines, each pump driving 4 airstones... hope thats clear...

you can see ive used a plastic rack thing to attach the airstones too, using wire ties, airline T-splitters and 12" airstones, two types in the pics, one the airtubing type of airstone - not very good imo, and the other 12" toblerone airstones...

the airstones are wired up in pairs... hope its clear.

DA-DA!

this bit is totally optional, and infact probably not that useful...

on my bigger bubs ive installed a front bit of tubing so i can see where the res is in the tub... a proper bung is needed in the hole at the bottom of the tub to make sure water doesnt leak out.

plumbing shops sell these.

voila!

time for a joint...

i'll be back.

MU big thumbs up mate. was it your thread where i asked what DWC was? in anycase i know now

Felon

cheers felon...

3 joints later...

right, how to run 'em.


because the roots dangle out of the net pots, then into a small space of air, then into the res, the roots are permanently in a highly aeriated reservoir of nutes, so underfeeding is the key to running bubs.

forget all about the ec's you hear other hydro growers talk about, like 1.1, 1.3 maxing out at 2.2 blah blah blah, it doesnt apply here!!

the ec of my water out of the tap is 0.2, so im lucky its quite pure, and here is my ec schedule for growing plants:

rooted clones thorugh the 3" rockwool cubes - 0.4
vegging medium size plants and mothers - 0.5
big plants 0.6
0.7 has always burnt my plants either in veg or flowering!
for flowering, start with 0.4 and work up to 0.6 in the last couple of weeks.

i understand this might be completely different under the lucas regime, so bear that in mind.

i have a syringe which measures in ml's so i can doses as low as 0.5ml quite accurately, but in a 50L res, for mums, i give 16/8/8 ml of GH Grow, Bloom, and Micro and that equates to an ec of 0.5 and my mums have been very happy for yoonks on that.

after a major prune, or clone take, i give a 3/4 feed, so 12/6/6, ec 0.4, because after a major prune they dont like so much food.


as for ph, i maintain a ph range of 5.7 to 6.1.

i have found with the 50L tubs this takes ages as the ph stays quite constant and the ec doesnt drop either, so you know the res is right if the ph is only rising slowly, say over 5 days and the water level is dropping, but the ec is staying the same or drops only 0.1 point in 5 days, thats when you know you have the res correctly set up.

once the res his 6.1 ph, its time for a topup and reset back to 5.7. if under strong lights the res may need topping up every couple of days, depending on how much water the plant is drinking. under flo's i only top up the res every 4 days or so.

when starting freshly rooted clones, i have had the best success with clones that have been rooted in 1" then 3" rockwool cubes, because the clone is quite well established by then, popping it the net pot and putting it in the bubbler, the clones are grown enough to take a feed of 0.4. ive had some problems putting in freshly rooted clones, from the bubbler cloner, with making the res too strong so i need to practice that a bit, might try an plain water res and foliar feed for a few days but thats offtopic here.

my point is, its easy to sting your freshly rooted clones with too much nutes when first installing them in the bubbler, so be careful...

also, when first installing the clones, heres how i do it... assume rooted 3" rockwool cubed clones

1- put one layer of clay balls in the net pot, only one layer so the roots dont have to work too hard to get to the net pot
2- plonk in the 3"rockwool cube
3- fill netpot with clay balls
4- install in bub
5- fill bub up so that the res level is a good inch into the netpot so the roots are already touching the reservoir and run the bubbler for the first week like this until a good number of roots have got through the netpot and are dangling in the res, only then should you reduce the level to just beneath the net pot. later on when theres loads of roots through, leave an inch or so between the level of the res and the net pot.
6- when first installing the young clones, if under HIDS keep the light well away, only drop the light when the clone is strong and plenty of roots are through the netpots and into the res... ive had problems myself with this, being too keen with a 600Watter on young clones...
7-check the levels and res temps daily and for a long time, until you have a good idea whats happening temp wise... if your grow rooom feels cold, then the res is probably too cold too!! if it feels hot in your growroom, really keep an eye on the res temps... i lost my 3rd bub grow, and screwed my 2nd one quite badly because of too low res temps through the winter.. i learnt the hard way..
8- keep an eye on your roots but dont lift the lid too much.. the roots dont like light. if your roots are going brown, try using cannazym and rhizotonic, which i use as a matter of course anyway because they really help to keep the res and roots healthy.

need a spliff!



edit: only install the rooted clones when there are a few cm's of several roots through the bottom of the rockwool cube, because the bubbler will saturate the RW cube and the clone will be starved of oxygen unless there are roots outside of the cube.

top-ups... i should mention those in detail.

i have been keeping mums in bubs for some time, and have found i dont really need to change the res for up to 3 weeks.

i usually do it every 2 weeks, but recently particularly as theyre going to be dumped soon anyway, ive been doing res changes every 3 weeks, and they still look fine and dandy.

what i do, is when the ec has dropped 0.1 i or the water level is dropping i give a topup of 4/2/2ml grow/bloom/micro, and with the extra water that maintains the ec at 0.5, it my rise to 0.6 sometimes, but the plants dont mind that and it usually reverts back to 0.5 anyway, so i find giving a topup of 4/2/2 and the required water every 4-5 days maintains the mum bubs well.

i also use 8ml of cannazym and 8ml of rhizotonic on each res change, but never include those in the topups, dunno if i should or not, but i only topup with nutes and use rhizo and cannazym at res change time.

talking of res changes, because i run big bubs, i pour the bath, after cleaning it thoroughly, and ph the water in the bath to 5.0.

i then fill the bubs by using a water pump from the bath through some tubing, into the bub, and then i give each bub the exact dose of nutes required.

i used to put the nutes in the bath but had loads of problems doing this, and was sure the nutes didnt mix properly doing that... so best to fill the bubs from the bath with just phd water, and then put the nutes in each bubbler seperately.

cheers all, hope thats been useful...

mu

oops, forgot to mention, the clay balls must be washed thoroughly and all the gunk removed...

otherwise your ph will go nuts!

i should explain that.

i ph the water to 5.0 because it always rises about 1 point when the bubs have been filled and the nutes applied.. it rises 1.0 point over 24hrs, always does that for some reason, esp if i didnt clean the bubs, which i dont always do.

so it initially rises to around 6.0 by the next day, i then reset it with some phdown to 5.7, and then the true 4-5 days cycle begins, the ph on drifts slowly, which is what is wanted.

excellent thread MU, i am about to soak my hydroton in readiness to fire up my 6 pot bubbler @ 7pm lights on.

when you say don't put a hole in the lid for the airline

i take it this is due to light leaking through the line & hole?

if so that's fixable so i am ok there, please tell me if it's for sommat else tho

quick Q about EC please m8?

when you say your water is 0.2 out of the tap and you then say that 0.7 is too high......

is that 0.2 background plus 0.5 nutes equalling 0.7 in total?

or do you discard the background ec and put in a 0.7 worth of nutes?

i only ask cos it's been doing me nut for a long time now and i would liek it cleared up but mainly cos i am sure my eau de council is way above your max levels already

cheers bud

hi mate



thanks buddy, and good luck with it!



well light getting in is a point, but (and i forgot to mention this ) i stick thick black tape over the holes where the airlines go, after the airlines are installed, just to further block out light..

but the reason not to put the holes in the lid is just because it makes taking the lid off for res maintenance and cleaning the tubs much easier...

i know this because i have to put the airline holes in my bubbler cloner in the lids and its a right bloody nuisance!



all the ec's i mentioned were total ec's as read on the nz truncheon ec meter, including the background ec.

so yes, an ec of 0.7 is 0.2 with 0.5 ec of nutes added, and thats been too strong for my plants..

so maybe if your starting ec is 0.5 for example, your growing range would be 0.6-0.9, i dunno for sure if thats right mate, so dont quote me on it... ive also heard that you should consider half of your background ec as available to the plants... im not too clued up on this, sorry!

ive just found what works for my water...

hope thats helped...

thats cool m8 ta

previous hydro grows (passive perlite) i have ignored the background and gone for what the truncheon says after adding the nutes.

1.4 ish for perlite noprobs.

afaicr my ec is 0.8 and my ph is 8.5 out of the tap, but it has been 4 months since i picked up my truncheon () so i will recheck all of that.

i will suck it and see, maybe start with an ec of 1.0 and see how i get on.

i am going to use citric for the ph balancing, this is new to me ( it's all bloody new ) as i am used to using phosphoric acid in liquid form.

here is my first attempt at dwc, i have made it so the lid just lifts off in 1 and the res can be replaced underneath, i have a few of these storage tubs lying around so i intend to just mix up a fresh res and swap over as necessary.

i have 2 airstones in there, with another pump and more stones in reserve.

quick tip for uk dwc'ers everything apart from the netpots and piece of plywood is from wilkinsons, they stock perlite too which can be used instead of hydroton, but if you got a big wilko's then J.A.Bowers make hydroleca which is little pebbles.

cheers MU, can't wait to get back into hydro

edited - i have a cover for the lid and sides of the tub made of b&w plastic, like a tablecloth with a rectangular hole in the middle for the netpots.

looking good, but im concerned you might not have enought airstones..


can we see inside por favor?

i would try 0.9 and work up mate.. plants burn easy in bubblers..

sorry, got another question.

what size res will that hold?

brilliant thread mu its people like you that make uk420 the best canna site.
interesting to see your e.c so low, during flowering in my bubblers i use an ec of 1.4 and although the plants seem healthy my p.h drops extremely rapidly and in 3 days it will have gone from 6.0 to 5.0, this is 1 plant in a 20l bucket filled with approximnately 16 litres of solution. maybe your low ec is the way to go for keeping a steady ph. i shall be giving it a go asap. thanks again mu.
i use the same ec in my 40 liter nft tanks and the ph rises almost as fast as the bubblers drop, this has been puzzling me for a while.

its a 35 litre tub, will hold 30 litres with the pots submerged 1 inch.

as soon as the mrs gets up i can start making noise (bloody nightshiftworkers)

i will fill it and see how well it copes, if it's crap then the other pump will get thrown into the equasion with another 2 stones.

the reason for using these tubs is that they will fit in my growroom.

i can get 2 in there and still have room for the odd soil pot.

i had planned on having 2 running with 4 pots in each, on a 1 month rotation, so i am cropping / flowering once every 4 weeks, but i am a bit ahead of myself as my mum stock is being rebuilt after the borg wars.

this 6 pot bub is being used to flower off all of the clones and stuff that was in the veg room recovering from the borg battles, time for a clean slate.

this way i get to get my feet wet with dwc while not having to fret too much about the stock that is going into the netpots.

the mums that are germing & vegging currently will require a working knowledge of dwc for me to be able to give them a half decent chance of reaching their full potential.

hi mate and thanks for checking out this thread..

i suspect your ec is too high in your bubs and the ph is dropping because the mix is becoming more concentrated as the water is being consumed faster than the nutes.

whats yoour starting ec?

sounds good to me ped...

that res of 30L should be fine.

be interested to see how your ec's dffer to mine, so please keep us posted...

mu i start the ec at about 0.8 for the first week and 1.4 after that for another week of veg then stay at 1.4 all through flower, i use lucas formula but without ro water but im lucky enough to get 0 ec tap water thanks to severn trent water from the welsh valleys. my ec is meazured with nz trunction, ive noticed americans use a different scale of ec to the nz trunction but they take there ec extremely high like 2.2

right i see...

tbh mate, youre ph should be rising, and slowly... if its dropping the mix is too strong... thats what i find with my bubs anyway.

the more concentrated the mix becomes as more water is consumed than nutes, the nutes drag the ph down.

if things are calibrated correctly, the nutes and water are consumed at the same rate, and the ph rises very slowly, and the ec remains constant or drops only slightly.

how the plants looking? have you tried a lower ec, see how they do? a jump from 0.8 to 1.4 seems quite a big one, do you rise up gradually? if the ph rises too quickly, then the nute mix is too weak...

Hi great post MU

any idea what the different flashing sequences mean?

I was gonna post earlier but it looks like you covered all my other questions

lofty

yeah, if its flashing between 0.4 and 0.6 it means its 0.5...

thats all the flashing you should get on a nz truncheon, ie between even numbers to represent the odd number... if its doing any other kind of flashing ooh err missus then i dunno mate...

I try to keep around 1.8 max but i get like 8 flashes @ 1.8 and four flashes @ 1.6 sometimes it alternates between led's so i'm none the wiser, If it goes up to 2.0 then i normally do a water change and i'm getting odd readings from the Seramis clay granules (couldnt get any H202 had to make do with Milton) when i add new pots.

cheers anyway dude watching with more interest from now on

Lofty

bugger

both my 55lph pumps arent enough to have an effect on the surface.

i tried with round stones and tbh its a joke, circles of bubbles above where the stones are located and that's about it. i think the water is too deep.

oh well , plan B

i have a 10 litre plastic tub with a lid, just begging to be used, i reckon i can get 2 pots in the lid noworries.

at least i've got something to do to get me out of the housework.

stronger pump and better airstones needed mate, not a smaller res - theyre a pain to manage tbh.

30L tubs are just right imo, quite easy to calibrate and get them running smoothly without massive jumps in ec or ph. deep is fine (it is DEEP Water Culture after all ) if you have a good pump... standard 150L dual outlet will be fine mate, can run 4 x 12" toblerones on that...

get aqua fizz if you can, google for them...

needs must as the wallet drives m8

i need a system to flower these clones in tonight, otherwise they're going to end up in passive perlite, cos they sure aren't ending up in the bin.

cheers for your help m8, i'm sure i'll be screaming for ya when me tips are frying.

good luck mate..

hi all been reading this thread intensivly over past days but im ready to start a bubbler but was wondering about 2 things really what size bucket you recommend for a 4 plant system?

and what airpump do you recommend for the bucket?i need a really quiet 1 cuz im in growing in the shed

this is my list of things needed so far please add if needed :-
+ one resivour (size dunno yet need answer)
+ airstone
+ airpump
+ 4 net pots
+ diahydro pebbles
+ Lid

Anythin else you suggest?

and what airstone is recommended need a good one?

masterly thread as usual MU

I'd really like to see some comparisons on grow techniques. I think the only thing I know for sure is organic produces the finest smoke. The rest is up for debate with me. I think in terms of growth rate, yield etc I wouldn't be surprised if the bubbler method, done to its finest, would be the winner. Your thread might have brought me one step nearer to giving it a shot actually.

cheers Mu. the quality is in the detail as usual mate.



loveweed

hi mate

a useful guideline is 4g per plant, which would equate to a a 64L res,. (4 * 4 * 4) but i have had no problems with less gallons per plant. for 4 plants i would aim for a res of at least 40L. the width and length need to be big enough to allow for 4 plants too, so it would need to be at least 60cm long and 40cm wide, thats the dimensions of my tubs and theyre perfect for 4 plants.

as for airstones, find an online aquarium shop that sells AQUA FIZZ 12" airstones, or at least 12" toblerone airstones - try to make sure theyre toblerones because they produce loads more bubbles than any other airstone ive used.

i would suggest for one bubbler of the size im talking about you would want at least 4 airstones, but i would recommend 8 so you can arrange them so that 2 airstones are under each plant - the more bubbles the better!

to drive 4 airstones, you could use 1 dual outlet 150L p/h pump, and to drive 8 toblerones, you would need either 2 x 150L dual outlet pumps, or 1 x 300L dual outlet pump.

dont make the mistake i made and use too few airstones. for a 4 plant bubbler i do think 4 airstones is the minimum you should have and 8 would be better.

you will need a few airline T-splitters, airline and some means of securing the airstones to the bottom... i use a rack thingy, other people glue the stones to the bucket - its up to you.

also, if youre in a shed, you will more than likely need an aquarium heater in the colder weather. do NOT put an aquarium heater by itself in a bubbler, because as the roots touch it, the area around the heater will be too warm, as the water is hottest near the heater. put the aquarium heater in an empty plastic bottle and then in the bubbler to stop the roots touching it, OR put the bubbler in a bigger tub with some water in it and the aqua heater in the bigger tub, and the bubbler in it too, so the inside tub gets the temp of the outside tub - hope that makes sense.

also, if youre in the shed, it might be easier to get 2 tubs, so when changing over, you can prepare the 2nd tub and switch the lids over for easy res changes.

as for noise, ive not really had problems with noise from the bubblers themselves, more the fans and compressor.

if you use a pump called SilentAir they are very quiet... also seating the bubbler on 4" of polystyrene, reduces the noise of the bubbler itself.

hi mate

thanks for the kind words of support.

come the autumn, i will be firing up the bubblers again, and this time will do a comparison between using the lucas formula vs the manufacturers guidelines for 3 part nutes.

ive been doing some reading on lucas and it seems to me the nutrient useage is very high under lucas so im interested to see how it will compare... following the lucas system, i reckon my ec would be "1.something" (at least double what i run with now), so it'll be interesting to see the difference.

cheers mate..

hi again just been out today got all my stuff apart from an air pump so now im scowering ebay and have found two that may be of use just need opinion

Four Outlet airpump

2nd Choice

i think the 1st link is best?

also i hope to expand in future due to some more space available at the mo ive got a 4 plant vegin room and 4 plant flowering room so was wondering will the 1st pump beable to run both bubbler boxes?

hi mate

both links go to the same page, but that first pump looks fine.. thats a 530L p/h pump if the max output figure is used, so should be fine.

that could run 7.2 toberlone airstones, so call it 8, which means it would be able to run 2 bubblers of 8 airstoines i would have thought.

edit: not sure if thats a total for all 4 outlets, or if you get 530L p/h per outlet.. if the latter, which i guess it must be, then you could run more than 8 airstones, im not sure why the minimum output figure is so low, theres quite a difference between the max and min figures...

in fact. 530L p/h out of 4 outlets could run 28 airstones, by my reckoning.

i just emailed the seller to ask some questions about it also do i need a non return valve so that water doesnt go back into the air pump or does that only apply to aquariums and for the airstones im gettin 8 12" aqua fizz air stones in each buckets is that ok?

its safer to get a non return valve but if you make sure the airpump is always above the bubbler especially when switched off, then there should be no return of fluid into the pump.

i dont use valves myself and havent had any problems. its up to you.

8 12" aqua fizz airstones will be ideal for 4 plant bubbler.