Help, tank crashing

[DMBoocock]

Got home, clowns (3 out of 4)all on bottom seem unable to swim/ maintain position in water. Tested nitrate, nitrites, ammonia levels all ok. Ph seems ok but a little on low side reading 8.0 rather than 8.1 what cuased this drop and how do i save fish

[cajen]

PH 8.0 shouldn't be a problem. Any inverts / corals? Do they seem OK? Check temperature, preferably with 2 thermometers. All pumps, skimmer working?

[DMBoocock]

All pumps and skimmer are fine

Shrimps and snails all seem ok

temp 27

GS reads 1.022

Any ideas?

[cajen]

Any marks / spots on the fish? Any other symptoms? Have any sprays (polish, air fresheners, etc) been used near the tank? What was the last feed you gave them?

[cajen]

If no ideas with all the above, try running some carbon and/or a polyfilter if you can - might be contamination from chemicals (outside the tank or warfare among some of the corals). And get extra aeration by pointing powerheads towards the surface.

[DMBoocock]

No marks that I can see, no white spot or skin blemishes.

Haven't been in the house since I fed them at lunch so deffinately no external contaminates.

Not sure what they had for lunch, either frozen brine, frozen krill or frozen marine mix but none of them are new so are what they have always had.

Oddly, since I've been buggering about testing everything I can think of, 1 of my falsies has joined it's friend and appears ok now, so the 2 clarkies are the only problem now!?

Have made absolutely no changes!

Have notices Cyano algae but added phosphate remover over a week ago to help with that.

[cajen]

Weird. Can you give a quick rundown of your setup / livestock?

[Wombat]

Do you run a calcium reactor? I had a similar problem once turned out the reactor had leaked and the inlet tube was immersed in the tank so the fish were gassed with Co2

It does sound like an acute toxicity to something