It's up to you on thepowerheads, 425's are sufficient I would think, BUT the 550's would do a better job of circulation in my opinion.
I have 2 425's in my 20g and am not toally impressed with them. The flwo seems so light. LOL
And the api test chemicals work the color chart is a little different though. But still the same basic concept, any green in ammonia and thats bad, anything but blue for the trites is bad. LOL
Do you have a refractometer? Great $30 investment and youre likely to never be off , unlike if you use the swing arm hydrometer.
Link for cheap one
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