Electric cooler for keeping roots cold in DWC?

In my latest (and first) grow, my plants came down with pythium. I don't currently have a way to cool my reservoir, so it's been fluctuating at the same temps as the grow chamber (70-90). I've been looking into some options for cooling the reservoir, and I don't want to spend 200$ on an ice probe/thermostat. Also, according to the manufacturer, the ice probe only drops ambient temperature by 6-8deg F.

So here's my idea. Use an electric cooler for keeping the roots cold. They are dirt cheap at only $28 on ebay: http://www.ebay.com/itm/Electric-Portable-Mini-Beverage-Personal-Fridge-Cooler-Warmer-Car-Boat-12V-DC-/121680385910?hash=item1c54b75776:g:GhsAAOSwjVVVgogu

I have a plug-in on-off thermostat to control temperature within 2 degrees (I made this for a DIY sous vide a while back). Anyway, I would like to buy one and try this out. I think I could get the water temperature as low as 45deg F. I know that oxygen is WAY more soluble the colder the water gets.

I'm inclined to keep the water as cold as I can, to get more oxygen in the water. My question is: can marijuana roots thrive at colder temperatures like 45deg F?

That small electric cooler won't be able to put out nearly enough BTUs to cool water used for a cannabis grow. The heat put off by the other equipment likely exceeds the capacity of your unit. There is no need to drop temperatures as low as 45 degrees. My plants don't negatively respond to temperature unless its under 55-60 degrees (in my personal experience). Pythium can be avoided via beneficial bacteria, enzyemes, and fungi as well. If you are growing hydro and run HID then you'll end up breaking down and buying a chiller (200-300$+ minimum).

I run 8 50 gal res's and 12 5gal buckets and never even check water temps. In fact, I have not cleaned a system in 12 months and with no worries of rot or root problems. Hydroguard at 3ml per gal and pondzyme makes life so much easier

superstoner1 said:

I run 8 50 gal res's and 12 5gal buckets and never even check water temps. In fact, I have not cleaned a system in 12 months and with no worries of rot or root problems. Hydroguard at 3ml per gal and pondzyme makes life so much easier

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That's because you hold so much water. Water has a high specific heat. The more water the harder it is to heat up. This works against you when you only have 1 single DWC.

Wait you run that many gallons and still use hydroguard? It's a great product but bro you are over paying for basic beneficial bacterias. They sell bacteria in a spore powder form which is much cheaper.

A 5gal bucket is about as small a DWC you should run, so water volume argument doesn't work here.

hydroguard at 3ml per gal is 150ml every 2 weeks. Considering the return and the lack of problems(none) that's pretty fucking cheap. just passing on tried and true experience, not asking for what you think I do wrong.

Changed buckets today. I think it is day 24 in flower.

superstoner1 said:

A 5gal bucket is about as small a DWC you should run, so water volume argument doesn't work here.

hydroguard at 3ml per gal is 150ml every 2 weeks. Considering the return and the lack of problems(none) that's pretty fucking cheap. just passing on tried and true experience, not asking for what you think I do wrong.

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Yes... You are running over 100 gals of water. You can't compare a 20gal hydro setup to a 100gal hydro setup. The difference in gallons is far too much. Additionally, Hydroguard doesn't last 2 weeks. Look at how and when bacteria and fungi are produced. You can achieve the same results with powder and use it more often throughout the grow. It will last longer, be cheaper, and you'll be able to apply once a week in order to maintain a steady and healthy bennie population. Those bacteria and fungi aren't meant to live past 7 days, so changing it every 14 days isn't doing too much good for you.

You are having a hard time with the math. I run 50gal res's. It's worked for years with no cleaning and no res temp control. No need to argue.

superstoner1 said:

I run 8 50 gal res's and 12 5gal buckets and never even check water temps. In fact, I have not cleaned a system in 12 months and with no worries of rot or root problems. Hydroguard at 3ml per gal and pondzyme makes life so much easier

Click to expand...

Wait so... x8 50gal res and x12 5gal buckets aren't RDWC?

No. 12 5gal bucket DWC and 8 50gal res's for aero rails and veg.