R-DWC system - clean and sterilise

[Rural Buddha]

ITMA (see YT vid below)

 

There is various advice for cleaning hydroponic systems on various websites. I've found several posts on here that also mention cleaning methods but didn't find a dedicated thread - so here's one

Now that I have finished a grow in my IWS Pro kit, I need to clean it.

So far I have:

1. Drained the nutes out.
2. Filled with plain tap water and left running for a few days (I couldn't do a clean right then due to a mini-crisis).
3. Used an old washing-up brush to do an initial scrub of res,, brain pot and pots.
4. Drained system.
5. Used watering can to add water as I scrubbed the brain pot and pots again.
6. pumped res., brain pot and pots as dry as I could with hand pump.
7. Filled system with ~150lt of tap water and added ~500ml of thick Domestos.
8. That has been circulating for about 7 hours now.
9. I'll clean the net pots, pot covers and air stones separately.

 

My questions are:

1. Did I use enough bleach? I've seen mention of 10ml/100ml ratio (1/10) - 1.5lt bleach to 150lt water. I have enough foam already
2. How long to run the system for with the bleach solution?
3. What else ought I do before using the system again?

 

Tagging the experts - @badbillybob, @stu914 and @zen-ken

All comments, suggestions and recommendations welcome.

 

 

[zen-ken]

 More than enough bleach.....run for at least 2 days

 

You can run some milton through after to belt and braces (the tablets are dirt cheap) but tbh if you cant shove something through it.... better just to replace the pipe for the amount you need imo.

 

Can't need more than a few meters....£5 odd for piece of mind 

 

(I use a bean stick and cloth and push it through the 25mm....the rest is bottle brush territory) 

 

1. yes
2. 48hrs
3. Get all the bleach out and clean or replace pipe (use it too wash the walls/floor with before chucking out)

Chillers can be left with clear white vinegar in for 24rs as well.....then tip it away before rinsing through with water.

 

[catweazle1]

Yes, 10 water to 1 bleach. Cheap thin bleach would be easier to wash away. Thick ones have something to make them stick to surfaces longer.

[Rural Buddha]

Thanks @zen-ken and @catweazle1

I would have liked thin bleach but the local supermarket didn't have any, I'll take a trip to Asda as they say their own-brand is thin - 0.38p for 2lt is a bargain! At that price I might run the thin bleach through to remove the thick bleach

Forgot to include that I'd reversed the pipes on the chiller and am running the bleach through it backwards - chiller is not chilling of course. I'll put some white vinegar it after I do the flush with fresh.

I was supplied with a 30m roll of pipe(!) so I have more than enough to replace it all, though that isn't something I thought I'd be doing after each grow. I'm worn out enough now - I'm not built to do a great deal of manual labour.

Milton tablets at Asda for £2.40 for 40 - presumably in the baby stuff section. I could add them to the plain water flush and not worry about flushing again after as no need to wash baby's bottle teat after before sticking it back in their mouth.

[zen-ken]

Remind me again....you ran the mykos packs didn't you ? 

 

If so, the pipes will be shit high....I dont replace all of it.....just the bits I cant get a beanpole through 

[badbillybob]

there are different types of bleach, i cant remember the specific details of the ingredient differences, but domestos is the one thats good for cleaning with.

i soak everything for a couple of days on recycling through the pumps, but despite this, the inside of the pipes eventually get stained anyway, and need replaced. 

i also scrub the pots with bleachy water and bleach the hydroton, but make sure and soak it in fresh water and re-ph it afterwards

[catweazle1]

Domestos: Disinfectant: Sodium hypochlorite 4.5g per 100g.
< 5%: Chlorine based bleaching agent (Sodium Hypochlorite); Non-ionic surfactants; Cationic surfactant; Soap; Perfume.

 

That's a lot of rinsing. You can put thin bleach on a surface, let it dry out and it's gone. You can even sterilise river water in a pinch with it for drinking. Sodium hypochlorite solution fully evaporates.

[Rural Buddha]

I used Mykos Root Paks in two of the net pots as a test to see if they made a difference @zen-ken - they certainly did!

I'll have gallons of bleachy water @badbillybob so will clean the Hydrocorn and everything else with it - bath and basin drains too as they run a little slow. Got to be careful with glassfibre bath tho.

@catweazle1 - Asda thin bleach says 'Thin Bleach contains amongst other ingredients: Disinfectant: Sodium Hypochlorite (available Chlorine 0.99g/100g)' - so ~4 times weaker but thinner. Maybe that's why it comes in 2lt bottles - more needed for correct ratios. Maybe it wouldn't foam up tho, that would be handy, could be the thickening gel in thick bleach that cause foaming. 1:100 seems to be the most quoted ratio for sanitising but I'm nearer 1:400 (got nearer 200lt in the system, not ~150). Perhaps Hydrogen Peroxide is easier, but at ~£35/lt (food grade) its expensive. I'll stick with the Domestos for the time being

Looks like I may be changing the pipes then, especially as I have plenty spare. Would enable me to position the filter in an easier place to get at.

[catweazle1]

27 minutes ago, Rural Buddha said:

I used Mykos Root Paks in two of the net pots as a test to see if they made a difference @zen-ken - they certainly did!

I'll have gallons of bleachy water @badbillybob so will clean the Hydrocorn and everything else with it - bath and basin drains too as they run a little slow. Got to be careful with glassfibre bath tho.

@catweazle1 - Asda thin bleach says 'Thin Bleach contains amongst other ingredients: Disinfectant: Sodium Hypochlorite (available Chlorine 0.99g/100g)' - so ~4 times weaker but thinner. Maybe that's why it comes in 2lt bottles - more needed for correct ratios. Maybe it wouldn't foam up tho, that would be handy, could be the thickening gel in thick bleach that cause foaming. 1:100 seems to be the most quoted ratio for sanitising but I'm nearer 1:400 (got nearer 200lt in the system, not ~150). Perhaps Hydrogen Peroxide is easier, but at ~£35/lt (food grade) its expensive. I'll stick with the Domestos for the time being

Looks like I may be changing the pipes then, especially as I have plenty spare. Would enable me to position the filter in an easier place to get at.

The 10% figure is for thin bleach.... that is what's called 'bleach'. Domestos sells on having other functions. It has similar acting chemicals as washing powder or washing up liquid in it as well. Just so you know for reference.

Edited November 20, 2021 by catweazle1