Red Tide killing snails?

[TomToro]

I now have a coating of reddish brown scum on the sub. It won't blow off with a baster and has to be scraped off. It sticks to the sand and gravel.

There are a number of snails that go to it, but don't leave. They're dead and the hermits won't go near them.
Q: Is this the red tide I hear about in the ocean or some cyano algae?
Q: How do I get rid of it (water change tomorrow of 30%)Larger?

Stats:3 halide bulbs are about a month old or so. Bought 'em last year, but didn't use them until last month. 10k hamilton 175w.
parameters are good except nitrates are around 30 today.
RO tfc membrane is 8 years old. Have one on order to arrive this week.
Reduced Halide time down to 8hrs from 10. No difference.
Increased flow to sub. No change. This stuff is sticky.
I'd appreciate any help.
Thanks,
Tom

 

[Fishieness]

red tide is a free swimming creature (saying creature because i am not sure if it is a bacterium or animal...) however, it does feed on thive in EXTERMELY nutrient rich environments. your animals probably wouldnt be surviving if you had red tide. it is most likely cyano bacteria based on the information given. you can siphone it out to help. But the best method is lowing your nutrient levels and frequent water changes.

 

[TomToro]

That sounds good. I'll increase my water changes from once a month to twice. Now I need some salt.

I also noticed in the morning the red scum is gone (even with the actinics), but returns shortly after the halides are on.

Thanks for the help,
Tom