Diatom Algae Help!!

[Sregnar35]

I'm starting a new thread for this topic because the other is getting long and I think it's being overlooked. Here's a quick recap...

75g, 40-50#LR, 3 in dsb(Southdown), hippo tang, yellow tang, 2 false perc clowns, royal gramma, mandarin dragonette. 3 maxijet 1200's, 1 HOB filter, CPR Bak Pak 2R with pre skimmer, 260W PC lights(new bulbs)on 9 hours.
Ammonia, nitrites, nitrates, phosphates - 0ppm
Calcium - 400-450ppm
ALk - Normal to High(no numbers on my test kit)
Silica - .5 to 1 ppm

The water I use is coming from either a local Walmart or grocery store, both test 1ppm silica, so it's obviously not the greatest. I have diatoms covering my sand bed and now starting on my rocks and glass. Does anyone have any idea's at all??????? I think it might be my source water???? PLEASE ANYONE, AM I OVERLOOKING SOMETHING??????

[mogurnda]

How many snails have you got? Diatoms are supposed to be turbo snails' favorite food.

[Sregnar35]

I have 2 fighting conchs, 1 big mexican turbo, 15-20 astreas, 10-15 nerite and bumble bees, and prob 10 of these striped red footed snails, they have a little horn like piece on their shell and they are striped. Mexican turbo's get kinda big, but the one I have really does a job on the diatoms, should I get some more, they're pretty cheap.

[mogurnda]

A few more thoughts:
It may not be diatoms, but rather dinoflagellates. According to Sprung's algae book, they look similar, but the treatments are different. He suggests increasing alkalinity (with buffers or kalkwasser), and using carbon to get as much of the organic stuff out of the water as you can. If your turbos stop moving and die after eating it, it's probably a dinoflagellate bloom.

On the other hand, all the silicate going into the tank is exactly what would fuel a diatom bloom. Finding a better source would help.

[Sregnar35]

Ok, my turbo I have now is def not dead, or even slower. I tried another store last night for RO water, but haven't tested yet. I'm getting ready to write a letter to the manufacturers of these grocery store RO water units, they must not change the filters enough, because 1ppm silica is waaaaaaay to high. I'm at the point now where I'm about 99% sure its my source water causing the algae,so until I find a better source, I'll keep plugging away at scooping out the algae and scraping the glass every other day!!! FUN! Thanks for all the help again Dave, you rule!!!

[mogurnda]

You're welcome, I guess. Not sure if I helped a whole lot.