Well guys I will have very intermittent internet for a few weeks. I'll try to get to everyone as I can. Here's a post I wrote a few days ago...
Well since the issue of PH has come up, we might as well explore it and some other aspects of brewing conditions. It's true that if you pour some bennies directly into a cup of pure PH adjuster they will die. So don't do that. Also keep in mind that PH correlates with microbe health/activity in soil much differently than our DWC. Just like plants, our microbes have evolved to thrive in a PH environment of about 6.5 to 7.5, but they are pretty flexible. Ideally, your tea should fall into that range. If you use pure water you should start out with something close to 7 and the molasses will bring it down a bit, so it will be close to perfect.
Adding Ph down, particularly GH PH down, can kill bennies if it's not diluted before adding it to the nutrient solution. If you add it directly to your res you could develop temporary hot spots and kill off microbes in that area. Of course, the way we replace the microbes makes this is non-concern, but it's still not ideal for the roots, so always dilute Ph adjusters outside the res first.
Room temperature is the best for brewing. If you heat up the brew to 80-85 you will greatly increase the microbe activity. This will also significantly increase the respiration rate of the microbes while decreasing the DO capacity of the water, which puts you in danger of an anaerobic tea. So if you have to brew a warmer tea for some reason, be extra sure to have adequate aeration.
Adding too much food initially can cause the microbes to multiply at a rate beyond the available oxygen, so don't over do it.
Brewing time greatly effects the type of microbes you have in the tea. Anything under 24 hours tends to be weak and have left over food. At 48 hours your tea will have more fungi and more diverse bacteria. Anything over 48 starts loosing nematode and fungal mass, but increases protozoa. When fighting disease we want the most diverse, which seems to be 48 hours at room temp. Different situations could require a longer brew.
I have such a slime problem that I can not clone in a bubble cloner, even with tea. No matter what I do, the bottoms of my cuttings turn black and form slime within a few days. I recently ran two bubblers side by side, one with bennies and one with DM Zone. Both developed slime at the same rate, although the Zone bubbler was less intense. I decided to a take a different approach. Instead of letting the cuttings hang over the water, I went ahead and placed them into net cups surrounded by hydroton. I then let them sit in a tray of bubbling water treated with tea. In essence, it's the same conditions as a bubble cloner. For some reason the cuttings not only resisted the slime this way, they rooted 100% within 10 days. The only difference I can see is the addition of hydroton which provided housing for the bennies in the absence of roots.
For people who are desperate and in danger of losing genetics, remember that cuttings taken from an afflicted plant should not transfer the disease. Also, i've saved plants by transplanting them to soil. Even with terrible roots they survived and recovered, although very slowly.
For those who just can't kick the slime no matter what, you may want to consider ebb and flow. When I grew ebb and flow my main res was full of slime, airstone was always covered, yet my plants never showed the first sign of caring about it. When the roots sit in air most of the time, the slime can't take hold.
It is normal for tap water to resist PH change, and in some places it's worse than others. The minerals in tap water act as buffers which try to bring the PH back up after adjusting, usually within a few hours. It's not until the buffers are saturated that the PH will remain stable. PH in a synthetic, disease free DWC should rise slowly and need adjusting every 24-72 hours, depending on res size and plant demands. If your PH is drifting it probably indicates disease, or could signify the presents of organic material being broken down. (sometimes broken roots or fallen foliage, organic PH adjusters, ect). The type of disease can sometimes be indicated by if the PH rises or falls. Slime tends to make it rise while pythium tends to lower it.
A RO filter will remove the buffer tendency from tap water, but will not help fight slime. The general speculation is that these spores easily get air borne and cover everything. I know of a guy who shut down his grow area for 3 months and ran an ozone generator and HEPA filter in his room the whole time, then cleaned every area with bleach. He then ran his water through a RO filter into a 55g drum which contained a large UV unit and was treated with 35% h202 and bubbled for 48 hours. All his grow equipment was cleaned with Physan 20. A few weeks later he was throwing out slimed plants. He switched to 'drip to waste' coco and had no further problems.
Lostrisinfast I believe your main problem is your nutes and ph adjusters. I think if you switch to a cleaner nute solution, such as Dutch Master, and use a GH liquid Ph down, you will see great improvement. Also, it sounds like you added the bennies directly to your res. We have found that brewing and applying the tea the way we described works best. If you used physan 20, be sure to rinse the roots well because it leaves a bio-static film. I would also worry a bit less about the PH flux until you have things under control. Don't drive yourself crazy.
I got similar responses from companies when I inquired about the slime. I think that most professional growers do not encounter it because they do not grow DWC style. I know my local hydro guy knows much less about DWC growing than other methods. DWC is well suited for small gardens, but gets less viable as the garden gets larger. I really doubt EZ Cloner has never heard of this slime, since i've noticed many of thier units being bundled with aquashield in the last year or so. Orchid growers know this slime, as do aquarium/reef hobbyists. Orchid growers simply use bleach or physan 20, aquarium owners use snails, fish, competing algae, or just wait it out. (Slime sometimes goes away on it's own after many months)
My slime problem is extremely tenacious, even after months and months of seeing no signs, it can come back over night if I don't properly use the tea. If I can successfully fight it, then there's hope for anyone. One good thing is that once you learn how to make it go away, you're likely never to see it again.