Water parameters

[mwe_ch]

So, since setting up my second-hand tank two months ago (saved all gravel and java fern plants and half the water), I have consistently had the same water parameter readings, but fish have been disappearing and/or getting ill left, right and centre.

I'm figuring some of the fish were old, and then others got sick from the stress of the move, and then 2 months in from the stress of a heat wave and a temperature spike.

So here are my readings:

Temperature: 26'C/78.8F (during heat wave went up to 29'C!)
ph: between 7.5 & 8.0 (it is this out of tap, tank has mangrove driftwood)
Gh: 12
KH: between 7 & 8
NH4: 0.5mg/l (meaning NH3 is between 0.009 & 0.03 depending on pH)
NO2: 0
NO3: 0 (planted tank)
PO4: 0.5-1.0mg
Fe: 0.25-0.5
CU: 0

The PO4 is a bit high for my liking today at 1mg.

EDIT:
(1) This is a freshwater 230l tank (hence why in FW forum), with established java ferns and other newer plants.
(2) The move took less than a day and fish were kept in the original aquarium water in a large insulated cooler with the original filter and that water was added back to the tank when they were reintroduced.

Any ideas?

-Michelle

 

[Crepe]

saltwater or fresh or brackish? Phosphate isn't much of an issue. I have phosphates up to 3ppm in my planted tank. I think you need to up your nitrates though otherwise you'll be in for some algae. The deaths probably came from the sudden change in water parameters from your place and the old place. The stress of moving also probably got them.