I need advice about my predator tank filtration :)


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Jul 16, 2017
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Hey Peeps,

I have a 375 Gallon Tank with currently:

9 big goldfish
1 baby silver arowana
3 baby motoro stingrays
6 medium discus

All living happily ^^

I have a 5x2x1 sump for this tank with overkill amounts of bio balls, marine pure and purigen. However, the water is always hazy. It is not cloudy, but not crystal clear either and I dont see any reason for it not being so. I have a 4 stage foam prefilter for my sump. I dont overfeed either.

I have a UV system on the way for the tank but looking at a few videos online, I am skeptical about it's performance in the clarity department. I have it primarily for safeguard against parasites as my fish are very expensive (fish cost a lot in Aust).

I was thinking of adding a fluval fx6 as a mechanical filter to the tank to polish the water. Is that a good idea? or is there something else I can try first
That's not a very good mix of fish, honestly. It isn't about temperament, it's about water parameters. First, discus require extremely clean water and virtually no nitrates. A planted tank works well for them where the plants take up the excess nitrogen quickly.

Meanwhile, goldfish aerie extremely 'dirty' fish, with a high rate of waste.

Exacerbating this is that discus are best kept in very warm water... about 80F or a bit more. Meanwhile, that is too warm for the 'cold water' goldfish. Goldfish kept in those conditions long term accelerate their metabolism, speeding up their rate of waste production (see the first issue) and dramatically shortens their life span.


As for the haze, get the goldfish in the right spot and the cloudiness will likely decrease.
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