I dont know who ever said the water cant be above 70 degrees farenheit, because that just isnt true. Mine is around 72-75 and is just fine. chamber smells like fresh vegetation when I have a sniff. And if light hitting your solution is an absolute no-no, then how do all those ebb & flow grows do so well? E&B water gets pumped up in to the resevoir 6-8 times a day, completely exposed to intense light for 15 minutes at a time... How come no-one ever says anything about the water/light situation then? I'll tell you why, history books are filled with people who condemn innovation. DWC is awesome. Not only is there no need for a seperate resevoir, but you can grow with the roots dangling directly in the solution itself. Everybody likes to say things like, "In DWC the plants drink more water than nutrients, leaving behind solutions that have highly toxic nutrient levels" Its no different from the nute soloosh in an ebb& flow, or peroidic tub feeding, or NFT, or a constant spray of Aeroponic solution directly to the roots. The plant takes up what it wants/needs and leaves the rest behind. Thats why we change our resevoirs periodically. DWC is too new to have the following it needs to have a bunch of tip rats jumping on the bandwagon yet, so that is why people still condemn it. Its called unfounded opinion - and there is no shortage of people who just talk based on what they heard someone else say or write. DWC is highly innovative, highly effective, and very cheap to produce and maintain. Algae grows in every hydroponic rez no water what, it is a large recirculated body of water and is succeptable to algae growth. Sometimes you cant see it but it is there, garaunteed. H2O2 does help immensley but be sure to only run h202 without nutes, because it breaks down the nutes in to unusable waste - which of course effects your plants uptake. I have seen some semi commercial type grows with outstanding results using DWC. Its all about how much one actually really knows about hydroponics. Alot of DWC bloggers say "First time grow", or "Help DWC plants dying", or "First time grower needs help DWC" You never see anyone write a thread that says "Help, Veteran DWC grower doesnt know what to do with all the weed he just grew". So its easy to spot only the bad in something so new as DWC. It is like anything else, you get better at it every time you do it.
Peace,
NYK