snails and dead guppies?

[fishycanuck]

Well, not a true emergency, but I'm puzzled.
I have a mature 10G tank with guppies, neon tetra, pleco, cherry shrimp and columbian tetra. I do a 40% PWC weekly and have done so for years. The newest fish were added around Christmas.
This week, I notice a crowd of small MTS on the glass. There are usually a few milling about, but this is a sudden shift. Today, a guppy died after swimming erratically for a few hours. He also had a frayed tail. Everyone else looks healthy.
All parameters are stable
Temp 80
No ammonia or chlorine
20 nitrate
0 nitIte
pH 7.2
The only change is I bought Big Al's Multi Purpose Aquarium Water Conditioner 2 weeks ago after using Prime for years. I measure with a medicine cup, precisely.
Wassup?

[dan2x38]

Excess MTS vacuum gravel well for next weekly WCs.  I would keep using Prime it is the best (IMHO).

[fishycanuck]

THanks, Dan - my DH bought the Al's variety 'cos it was "so much better value" 

[dan2x38]

I am not sure all that stuff even removes chloramine? You are on City water? It has chloramine but you know that... Prime works out quite cheap. Only need 1 mil for 10 gallons one capful for 50 gallons. Me I dose for the entire volume no matter the size of my water change. During spring or heavy rains I double dose at the least just to cover possible excess chloramines added by the City. With this spring I think we have a freakin' whack of nasty stuff in all our waters so they are dumping a pile of chloramine I bet. I've not visited the City's site for water treatment readings lately but would be willing to bet it will show markable increases in their water treatment scenarios.