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FrostyGreen

NEW RDWC SETUP - RESERVOIR INFORMATION

Hi fellow growers!

Would like to start of by saying what a brilliant forum this is and excellent advise and ideas put forward by everyone and ive leant a lot from this forum in the process.

Im going to make my post as short and as concise as possible so I don’t bore anyone to death!

So im an absolute newbie, never grown a tomato! however have been reading for some time and have leant in the ins and out (compromises) of each growing method now and have decided to grow via RDWC (DIY) as I can’t justify the high prices for ready built systems.

 

Will be building a 650 litre (total Volume) RDWC (x18 35 Litre Buckets, appropriate chiller, inline water pump and x2 or 3 Hi blow air pumps with 3 inch pvc pipes with bulkheads not uniseals -  I know it’s a big project/operation for a newbie!)

The question I had was relating to the Water Tank (Top of Reservoir) Im currently reading into and understanding the nutrient solution mixture process and different methods and causes of readings of PH, TDS, PPM etc to go up and down.

As far as im aware in a RDWC system you need to have minimum Auto Top of Reservoir Capacity equal to the system Volume (in my case 650 litres) plus if possible another 10%

The problem I have is that the way the room is shaped I am unable to fit a say a 700 litre flexi tank or something similar in there due to the size of the tank itself as well as the room shape. I am also unable to adjust the buckets configuration to be able to fit the tank even reducing a row of buckets.

As far as I have read you mix the nutrients in the reservoir (according to water volume of course) and then this feeds the epicentre with the required solution according to the auto top of valve via gravity in order to maintain system volume and nutrient solution for the plants.

I also believe the more water you have (ie bigger system with more water) the easier it is to maintain PH fluctuations etc.

Coming back to my question – Everywhere I have read everyone says minimum tank volume should be the same as system volume.

What I want to try and do is say try and fit a 300 litre res tank in the room instead of 700 litres as it is smaller of course.

Is this possible on a 650 litre system? To me common sense tells me that you would mix nutrients in the 300 litre res tank same as a 700 litre tank but obviously with less of each as it’s smaller.

I know I would be refilling the res tank more often (especially in later stages of growth) or doing a nutrient solution change more often as I have smaller tank than the system itself.

But again I am unable to find an answer as to why you are not able to have smaller tank then the system volume? Or Can you?

Just to add, I am aware that putting the res tank outside the grow area is recommended (keep water temps in check – from the Hps lights) but I don’t have another room next to the grow room but I could keep the res tank away from the HPS lights if kept in the same room – smaller tank though!

 

Some parts are here and working on the rest. Would like to do a build diary when all bits are here and put together hopefully.

Would greatly appreciate any feedback/input from members ( especially BADBILLYBOB!) to help me out with this res tank dilemma I have!

Thanks in advance and keep growing big!

 

Cheers

Frosty Green

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Hi bud and welcome,

 

I suggest you start off by growing in compost, nice and simple, learn how to grow before getting involved with complicated hydro set ups.

 

Whichever you choose I wish you the best of luck

 

atb

stu:oldtoker:

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Posted (edited)

Hello, 

I don't know where you read about needing an auto top up res  the same capacity as the system. You don't.

 

I don't use res top up tanks at all, for the simple reason that its best to renew the nutrient in these systems every 7-10 days, especially in bloom. So you would be drawing very little nutrient from the top up tank before having to dump the nutrients out and re-fill it .It would be a waste of nutrients and cash

IN veg you would get 2 weeks out of a system  fill, at most, so you would never be topping up that much from the top up res. 

If you  do decide to use a top up res,  you would also need to floom the top up res (basically a small pump in the bottom of the res, worked off  a timer to keep everything moving. about 15 minutes - three times a day would do it. The only reason for using a top up would be if you had limited access to your grow area, and even then I would be afraid of the top up float valve sticking and flooding the place

 

Your system also wouldn't hold 650 litres, because your 35 litre buckets would only have about 20-25 litres of nutrient in each, depending on the size of net pots used. You would be nearer 400 litres. 

You will also need a chiller - Hailea HC500 maybe?

 

Are you using bulkheads on round buckets? If so, what diameter are they?

Oh and you are right about uniseals, they are crap , I wouldn't use them , again lol

 

Remember and start a thread if you decide to go  RDWC.

and good luck

 

Edited by badbillybob

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Posted (edited)

I'd go for the 300L tank and do a 300L res change every week, instead of a full change every two. It's not exactly the same, but I you'll be fine if you monitor PH/PPM every day and keep things dialled in. 300L will be more than half of your existing res.

Edited by SevernValleySavant

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Hi Guys, and many thanks for the quick replies.  What you suggest Badbillybob makes sense and that was what I was thinking and also what Servernvalleysavnt said also makes sense too.

I was aware of keeping a submersible pump in the res tank to keep nutrient solution mixed well and also maybe a water temp monitor in there as well.

Yes and also about the useful volume (capacity) of the system is usually about 70% so would be around 400 litres like you said badbillybob and would be using a haliea HC500 chiller also. Would be using 8 inch net pots with 50cm plant centres.

To answer your question – I will be using square ABS food grade boxes as I know bulkheads aren’t really suited for round buckets and the cuts out will be 3-7/8 inch hole for a 3 inch bulkhead with gaskets on.

This leads me onto the next questions if I DONT have a RES tank (ideal if I didn’t!) as you mentioned.

1. When plants use up nutes from the water in the system the water solution level will drop(ie overall nutrient solution in the system) so how would I keep that topped up if I didn’t have a auto top of res with correct mixture in the res tank?

2.From what ive researched its best to mix nutes in res tank SLOWLY and not the epicentre (plant shock etc) especially when you need to correct ph/ppm etc, so how would I do/control this if I need to do a nutrient mixture adjustment within the week before a complete change out and didn’t have auto top res tank?

3.Again if I didn’t have a res tank, how would I fill the system completely? Manually pour water into epicentre – id get 35 litres in the epicentre first – how would I get the rest of the buckets filled up to the right level (inch underneath bottom of net pots)? And then on top of that mixing the nutes to the right level and knowing the readings are equal in each bucket? With a res tank which will have the right nute mixture already in there I could just pump out the nute solution via hose pipe from the res into the epicentre?

These are the bits im confused on – with regards to the rest (building the rdwc, connecting pipes, b heads, connecting air manifolds with the hiblows and the chiller to the epicentre and of course room figures with regards to temp, ventilation and humidity at different stages of growth , I believe im ok with that).

Once I have established and got my head round this Res tank issue I will definitely start a thread when building it.

Look forward to any input and clarification guys. Thanks in advance

 

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Posted (edited)

30 minutes ago, FrostyGreen said:

Hi Guys, and many thanks for the quick replies.  What you suggest Badbillybob makes sense and that was what I was thinking and also what Servernvalleysavnt said also makes sense too.

I was aware of keeping a submersible pump in the res tank to keep nutrient solution mixed well and also maybe a water temp monitor in there as well.

Yes and also about the useful volume (capacity) of the system is usually about 70% so would be around 400 litres like you said badbillybob and would be using a haliea HC500 chiller also. Would be using 8 inch net pots with 50cm plant centres.

To answer your question – I will be using square ABS food grade boxes as I know bulkheads aren’t really suited for round buckets and the cuts out will be 3-7/8 inch hole for a 3 inch bulkhead with gaskets on.

This leads me onto the next questions if I DONT have a RES tank (ideal if I didn’t!) as you mentioned.

1. When plants use up nutes from the water in the system the water solution level will drop(ie overall nutrient solution in the system) so how would I keep that topped up if I didn’t have a auto top of res with correct mixture in the res tank?

 

get a 40 litre rubble/ laundry plastic holder from B&Q , and mix your nutes up in this, then add it to the res epicentre

2.From what ive researched its best to mix nutes in res tank SLOWLY and not the epicentre (plant shock etc) especially when you need to correct ph/ppm etc, so how would I do/control this if I need to do a nutrient mixture adjustment within the week before a complete change out and didn’t have auto top res tank?

see previous answer



3.Again if I didn’t have a res tank, how would I fill the system completely? Manually pour water into epicentre – id get 35 litres in the epicentre first – how would I get the rest of the buckets filled up to the right level (inch underneath bottom of net pots)? And then on top of that mixing the nutes to the right level and knowing the readings are equal in each bucket? With a res tank which will have the right nute mixture already in there I could just pump out the nute solution via hose pipe from the res into the epicentre?

Well this is what I do. I add a length of hose from the pump in the epicentre, and pump the old nutrients into the nearest sink/bog/drain. This empties the system. 

then I fill up the 40 litre rubble/laundry bucket type things with clean water (which has the added advantage of containing chlorine, which will help keep things sterile) and fill them into the epicentre, then add nutrients,  or......if I cant be arsed with all the lifting, I will fill the bath, mix up the nutrients in there,  ph it, and pump it from the bath to the epicentre. you will need more than one bathfull for your system. Filling the epicentre will also automatically fill the buckets, because water will find its own level.

These are the bits im confused on – with regards to the rest (building the rdwc, connecting pipes, b heads, connecting air manifolds with the hiblows and the chiller to the epicentre and of course room figures with regards to temp, ventilation and humidity at different stages of growth , I believe im ok with that).

Once I have established and got my head round this Res tank issue I will definitely start a thread when building it.

Look forward to any input and clarification guys. Thanks in advance

 

 

replies in red above. 

Edited by badbillybob

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have you got a link to your boxes?

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Thanks for the reply Badbillybob, will look into your suggestions, although i wont have a bath near by!, will have to figure this out but i get the gist now!

 

Dont have a link for my buckets unfortunately as i know someone who works in a container factory abroad and he got these made for me.

 

Once i get it going you will be able to see them on the pics when i start the build thread.

 

Thanks

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