Quote Originally Posted by aylad View Post
Shock level in a non-stabilized pool is 10 ppm. Last night I read through several threads about water mold (which is apparently common in Baquacil pools that are more than a couple of years old), and shocking/filtering seems to be the answer, just like it is with algae. In an indoor pool, once the algae and mold are dead it may take some time for your chlorine to come back down to swimmable levels, but on the up side you don't have the sun to compete with when you're trying to maintain 10 ppm!

If you haven't already read through it, take some time to read through this thread about Borates at http://www.poolforum.com/pf2/showthread.php?t=4712 . There was originally some experimentation with borates at 50 ppm to see the effect on rising pH on pools with SWG, but a side effect of the borates seems to be that there are some algaecidal properties. Understand that borates alone won't do the job--you still have to maintain adequate chlorination--but they may help. I don't know much about the health concerns of borates since I haven't raised the level in my pool yet, (haven't finished the research) but there's been some talk around the forum (and it may be in the above thread) about not letting your pets drink from the pool with a high borate level.

Regarding your filter.....several of the forum members use a cup of DE in their sand filters to help filter finer stuff out of the water, but I believe I've seen warnings not to do that with a cartridge filter because the DE gums the filter up. (After I post this I'll try to find that thread and add it here if I can find it). I don't have much experience with cartridge filters (mine is sand), but sine the filtering media is so tightly woven in a cartridge, I would think that DE would plug it up--especially if you're adding a cupful. Hopefully someone around the forum with more experience with cartridges will chime in with an opinion soon!

Janet
I recently switched from an older Pentair DE to a Pentair Cart (water restrictions in area made backwashing problematic) and my specs indicate that you should use cellulose fiber instead of DE as a filter aid for the cartridge. I was already using CF-138 (a brand of cellulose fiber) instead of DE for my old DE filter so I am now using it with my cartridge. I was always told (by Waterbear and others) that DE would plug your cartridge. The stuff isn't as cheap as DE but is safe for the cart. The funny thing is my manual says to add a cup or so until you get a 1 lb. increase in pressure. I can add multiple cups and my pressure never rises.

Mike