this is my first and i look forward to learning a lot from this forum (already did by reading various threads!)
we just bought a house last fall and this is the first season of us using the pool.
information about the pool, based in New Jersey - 24000 gallons, use DE filter, i use BIOGARD products (shock, back up algae, and polysheen weekly, plus keep 3 chlorine silk sticks in skimmer)
latest test readings:
Chlorine - 10 (high so i am not adding silk sticks)
tot alk - 272 (adjusted alk 224)
CYA - 160
Tot. hardness - 205
saturation - 0.5
i've had very a couple of medium size brownish spots in the deep end of the pool - they did not respond to brushing but i think they faded in color some once i shocked the pool. i kind of left them alone and perhaps i should not have. then in one area of the pool in the shallow end, i had spots forming that looked like scale, hard to the touch, sand like - also could not brush them off. these spots looked like what we've seen in biology class when you put two glass sheets together and the water and the liquids formed those "ameba" shaped forms and the like. forgive me if the description is a bit odd but i am trying to do the best to describe it.
then, i had the water tested last Tuesday by the pool store and they recommended i added Biogard balance pack 100, 25 pounds split into 3 applications. i did that and now i have these ameba-looking spots all over the floor of the pool. again, they are hard to the touch and dont brush off using a regular brush (not metal bristles).
i went to the pool store again last evening and they have recommended, based on their tests and my description, that i add 2.5 quarts of Biogard Scale Inhibitor. i did that last night. i had left the pump running overnight but this morning i see no changes.
to lower alkalikity, i also added 1lb of Biogard low n slow this morning; will do the same tomorrow morning as well - all told by the pool store of course as i am a newbie at this.
i am worried that i am not getting the right recommendation from the pool store. i've read up online, including this forum, that this could possibly be mustard algae that at times becomes sand-like vs. slimy types of algae. mustard algae seems to be able to fight chlorine so it's possible i have this type of algae despite relatively high level of chlorine in my pool (10 currently albeit there is no discomfort at all swimming). also, given my high chlorine level, i also think i've read that my other tests could be wrong so i am a bit at a loss as to what to do next.
i am hopeful i've provided sufficient information for you folks to give me some advice. please let me know what else i could provide for you to help you determine what i've got.
many thanks in advance!