New 72 Bow Front Tank

[scottyd1119]

Hi all
I'm new to saltwater tanks and recently purchased a 72 gallon bow front tank with an overflow built in. I have a pro flex 100 for a sump with Fiji Mud in it. I've been cycling the tank now for about 2.5 weeks with 90 lbs of live rock and 80 lbs of live sand. I first tested the tank 3 days after setting it up and my ammonia was 8+, my nitrites were 5+, and my nitrites were 5. Last week i tested it again and my ammonia was still 8+, my nitrite was 5+ and my nitrate was 10. Earlier this week i tested again and my ammonia was .25, my nitrites were 5+, and my nitrate was 160+. I did a 50% water change to lower the nitrates which lowered my nitrites to 1.0 and my nitrates to 80, and then last night i did another 50% water change and my nitrates lowered to 40. I know its recommended to not do water changes but i thought that the nitrate levels were too high. Should I stop with the water changes and just wait till the ammonia and nitrite drop off or should i keep doing them to keep the nitrates lower, and if so what levels should i be aiming for. Thanks for any help you guys can give me.

 

[ryshark]

Those numbers seem extremely high. Are you using RO/DI water for make your saltwater and do top-offs? Typically you are suposed to not do any pwc until the cycle is complete. You are aiming for 0-ammonia and 0-nitrite. After you achieve that I believe you can focus on lowering the nitrate before you and any fish.

 

[scottyd1119]

I'm using spring water for now, after the tank has cycled i was planning on doing a 100% water change using RI/DO water. my goal is to get the ammonia and nitrites to 0 but i was affraid with the nitrate at 160 that would hinder the bacteria from surviving and growing.

 

[pat8you]

ammonia and nitrites need to be 0 before you can add anything. nitrates can be lowered by water changes and macro algae. I would shoot for under 20 with fish only and under 10 for corals. With a reef tank you really want to have your nitrates at 0-5 if possible.

 

[scottyd1119]

I'm not planning on putting fish in for another 4 weeks or so until the tank fully cycles. I know that there needs to be no ammonia or nitrites and the nitrate needs to be under 20 while fish are in there, i was looking to see if anybody had any guidelines as to where to keep them under while cycling a tank.

 

[Kurt_Nelson]

I'm not planning on putting fish in for another 4 weeks or so until the tank fully cycles. I know that there needs to be no ammonia or nitrites and the nitrate needs to be under 20 while fish are in there, i was looking to see if anybody had any guidelines as to where to keep them under while cycling a tank.

Sounds like you're fine. Really high ammonia during a cycle, like you had, just seems to prolong the cycle. It could even stall it I suppose. But it sounds like your tank had gotten over the hump since the ammonia dropped off so much. You just needed to get over the nitrite hump. Having excess nitrates in the tank during cycling doesn't hurt anything. You could've just left it with no water changes and let it finish out the cycle. But what's done is done.

Sounds like you were pretty close to the end anyway, and you should have a fair amount of bacteria. I wouldn't do anymore water changes though, and let the ammonia and nitrite levels zero out, and stay that way for a couple days. Then go ahead and do your big water change. If you do a 100% change, just don't let stuff stay out of water for very long.

If you wait more than a week after the tank cycles to add fish, make sure to "feed" your bacteria. They need an ammonia source to survive. Your fish will normally supply that. But with no fish, you'll have to put a pinch of fish food in there every few days to give your tank something to break down into ammonia.

 

[cmor1701d]

You should use RODI water for all PWCs. Sprint water contains who know what as far minerals are concerned. Distilled water would have been the better choice.
As Kurt said, a 100$ water change is a bit drastic as the rock, sand etc. wil be dry for a period of time. I would do several 50% water changes over a weekend instead. That should get your nitrates down to a reasonable level. Under 40 is fine for FOWLR, under 5 is the goal for a reef tank but that takes time, tank maturity, pwc's, macro algae, etc. to accomplish.

My tankl also hit 8+ for ammo when I first cycled it. I used a lot of uncured LR and added a couple of shrimp too. No big deal, just a longer cycle. You are near the end of yours. Good luck. Just go slow and you should be fine. Oh, and ......