I apparently just killed all inhabitants of my 15gal non-CO2 Excel tank.

Humphead glassfish, Ram, and a couple tetras. The 15gal serves as a Q-tank/holding tank, and is moderately planted.

I dose EI at about 2/3 once per week, with weekly 50% wc.
I usually dose Excel in this tank according to instructions.
At water change the tank usually gets 7.5ml Excel (as per instructions), plus 1.5ml (which is 1.5x strength maintenance dose) about 3x per week.

Yesterday did usual 50% water change but because of inaccurate pouring, the tank got about 11-12 ml of Excel (1 full capful, plus a second full capful that spilled over a ml or two as I was pouring). I therefore dosed about +4ml more than instructions. Doesn't seem like a lot but perhaps that pushed the fish over a threshold.

Of course let this be a lesson for those smarter. Do not pour over tank.

I believe the cause of fish death was Excel overdose, so I am curious of others reactions and experience on fish tolerance limits to Excel.

Shouldn't over dose the water change dose, just the daily dose


15 gal = 7.5 ml @ WC, 1.5ml x 2 = 3ml @ double daily dose.


I agree with your assessment. At levels above what I listed, fish do act stressed.

See attached pic for my solution to the measuring problem.

In front is some sort of medicine doser available at your local drug store (got mine at Rite-Aid) -- measures up to 10 ml. In the back are 2 bottles.

The one on the left (my 4dKH water for the drop checker) I got from Rite-Aid -- it has about a 1/8" hole for dispensing which is about as big of a hole as I would go with.

But, the best of all is the white bottle on the right (my Prime). You can buy some cheap plain saline solution (for contacts) at your drug store and pop the lid off with a screw driver and fill it up after rinsing. Be careful removing the lid as it is not made to be removed and you could damage it. These bottles have a very small hole. You can squirt a small stream and stop dispensing at 5 ml or any measurement with ease -- you can even do drops very easily. The saline bottle has saved me tons of time (and stress).