SO..... I've come to the conclusion that phosphate is not only a favourite food for algae and plants.... but perhaps extremely toxic to inverts such as snails, starfish, and crabs. Is this so? anyone know for sure?

Here is why. A little while ago I couldn't seem to keep turbo snails or hermit crabs. They wouldn't last longer than a day or two. Water params were this:
Ph: 7.9 - 8.1
Alk: 8 dkh
Calc: 400ppm
Am: 0
No2: 0
No3: 20ppm
Phos: 1 ppm ... yeah that's high.

Keep in mind that my Coral beauty, clown, neon goby, and 2 Kuda seahorses are doing great...even now. But no crazy algae growth. The No3 level of 20ppm shouldn't affect the inverts as many have kept them at that or higher before. And the tank or LFS that I got them from, the No3 was higher at about 50ppm and living fine for weeks. I know as I work there.

I was recently able to bring the phospates down to 0.25ppm and No3 to 10ppm so decided to give blue leg herm crabs a try since they seem to fare better. I've had them for over a week now and they're cruising around as they should! So...just yesterday (the 15th) I bought 1 turbo snail... he seemed fine overnight, but today I have to constantly fix him upright as he keeps topling over from "weakness".

Water params are this now:

Ph: 7.9 - 8.1
Alk: 8 dkh
Calc: 400ppm
Am: 0
No2: 0
No3: about 15ppm
Phos: just below 0.5 (hagen kit :rant: !)

Is phosphate this toxic to inverts?! And on another note, I think I know why my phosphates and No3 keep giving me trouble no matter how much or frequently I change my water using ro/di water and Instant Ocean (I/O) salt mix. One word... SUBSTRATE! Check out my other thread I'm about to start title SUBSTRATE INFO! Just FYI!!!