First tank in years question.

[merlin69]

I bought a tank from my sister. Its been up and running for years with nothing in it. Its a 50 gallon double hex tank. I took about 1/4 of her water, the live rock and substrate which is about a 3 to 4 mm crushed coral. Its got a Fluval 305 pump and a small power head in it.I cleaned the filter which was almost certainly completely clogged. I've also add activated carbon to the 305. I don't have anything other in it right now. I tested the basics PH, ammonia, nitrites and nitrates. Everything looks good but the nitrates, they are out the roof. Just for the heck of it, I tested my tap water which I know is not ideal to use and it had zero nitrates.

Is there a probability that she had lost bacteria in her tank as there was nothing for it to consume?

Once I get the nitrates down with water changes, will I need to pick up some type of seeder material to help establish a new bacterial base?

My plan is not to rush it, a couple smaller fish and then eventually replace the lighting to support some easily to raise soft corals.

Thanks Doug

[zooman72]

The nitrates point to previous bacteria converting ammonia and nitrites, but while some may (and probably do) remain, they will need time to reestablish their numbers to handle new fish. Research a bit on new aquarium cycling and the use of ammonia (or other biomass such as raw shrimp for example) added to start an aquarium cycle before adding any fish.

Also consider looking into replacing that substrate as crushed coral by itself is difficult to use and keep from becoming a debris trap. Take a look at finer substrates such as CaribSea Special Grade aragonite or something similar in grain size. Also look into a phosphate test, as it can be even more of an issue in the long run, and you may have a significant amount bound to your present substrate and live rock. Once you put lights over the tank you may be surprised with a substantial algae bloom if you have higher phosphate levels.