First water change question

I have set up a 34 gal cube tank. I started with cured live rock. 20 lbs of bagged live sand and 10lbs of live sand out of a tank at the lfs. I also filled the tank with salt water from the lfs. My tank was setup on Thursday and on a reccomendation from the lfs guy I added a Blue Reef Chromis and a Black and Gold chromis, along with 2 hermit crabs on The next day, Friday. I did my first water quality test on the next day, Saturday and got the following Results: pH 8.2, Ammonia 0, Nitrite 2.5, Nitrate 5-10ppm, Specific Gravity 1.025. Then one week later I did my second water quality test, 9 full days later and the results were : pH 8.0 - 82, Ammonia 0, Nitrite 0, Nitrate 20 - 30ppm, specific gravity 1.023. I have been replacing evap. with RO water purchased from LFS. Finally my question is since my Ammonia and Nitrite levels are at 0 and my Nitrate levels are rising above the recommended >20 ppm. Is my Nitrogen cycle working? And should I be planning a water change? I don't want to to do it too early and the cycle question is just for peace of mind I will not be adding any livestock to this tank till at least 3 weeks from intial setup, according to the recommendation of my LFS guy. Thanx ahead of time for the recommendations.

 

Great work so far! And Welcome To 3Reef!!!

Sounds like you're doing everything right. Had I not bought this book a week or so ago, "Marine Reef And Aquarium Handbook" by Robert J. Goldstein, Ph.D., I wouldn't have known this. Apparently, after ammonia and nitrites go to 0, nitrates begin to accumulate. When they reach levels of 20-30 is when most do their first water change. This is what I have always done.

But deep within anaerobic crevices and pockets in good, porous LR, live bacteria that change nitrates to harmless nitrogen gas. Just as the first and second waves of bacteria need time to populate to combat first ammonia, then nitrites, so does this anaerobic bacteria to conquer nitrates. If given enough time and good quality porous LR, all that nitrate can be broken driven off into nitrogen gas. The whole idea behind building up a good stock of beneficial bacteria is to have sufficient numbers of them to rid the tank of ammonia, nitrites and nitrates the instant they're produced--with an end result of these 3 items never having a chance to accumulate in the water.

The author of this book claims that if all goes right, after 10-12 or 14 weeks, all traces of ammonia, nitrite and nitrate will be gone. At this point, the tank is fully cycled and ready for any livestock you wish to keep. (Appropriate to the environment you create, of course).

As a disclaimer, I have to say that I've often read one thing, and then something completely opposite in publications, and even more so on internet forums. It seems that as far as we've come in this hobby (and we've come lightyears in just the last 15 years or so), we still don't know it all, and you'll find for every argument there's an equally valid counterpoint. It all depends on your sources, who you trust, and on what you base your decisions.

Good luck, TenUhC!

 

Well Ishould have more than enough live rock. My LFS said this rock had been curring for over 2 months and I got just over 50 lbs. Shelf and very pouruspieces. Also my tank is a Red Sea MAX 130. It's 34 total gallons but only 29 of that is usable for display so my rock is good. I don't want to sound dumb but are you saying from your book I should wait or do the change. I only need to do about 5 Gal. changes I believe so I got a 5 gal bucket, a new nano powerhead and a 50w heater. I figured I could send a friend down to wallyworld and he could get 5 gallons of RO or purified water. And I could mix my salt water tonight and after a salinity test be ready to doa change 24 hours later. So I'm ready any which way I need to do it. I'm a big fan of leaving it but don't want to kill any thing good bacteria or livestock. I want this to be a no death zone. lol.

 

Not a dumb question at all. I actually didn't say either way. I tried to be pretty comprehensive with the facts to let you make your own decision.

The pros and cons:
Pro's: The nitrates that have developed will be diluted in whatever percentage you change your water. Do a 20% water change and you'll get rid of 20% of the nitrates you have. You can add nitrate sensitive fish and invertebrates sooner this way. Nuisance algal blooms will be mitigated by a lessening of nitrates.
Con's: If you do a water change, the bacteria that change nitrates to harmless gas won't have a chance to develop. Over time, those nitrates can accumulate more easily with no bacteria in place to keep them in check. Nitrates are actually beneficial food to most corals and definitely for macroalgae. It's only certain fish and invertebrates like shrimp that have little tolerance to nitrates.

Maybe some others will chime in.

Personally if it were me, I'd give it time, and just avoid adding inverts for now. When the nitrate consuming (nitrifying) bacteria populations become sufficient in number, nitrate levels should suddenly plummet.

Please let us know what you decide and how it goes. I'm subscribed.

 

I'm wanting to wait myself just don't want to cause the 2 chromis' and hermits trouble.

 

I would wait then. By how it sounds you will have a stronger bio system faster if you wait. Why process everything to NO3 when you can process it all right out of the water?

 

Wait, maybe I am reading wrong, but didn't you say that you already have fish in there? If this is so, and you did not see spikes in the ammonia AND nitrite, then maybe you have enough bacteria all togethr already set up in the LR so that you pretty buch skipped your cycle. I would do a water change just to dilute it, because I think the beneficial bacteris that kills nitrates lives in your rocks and filters, not so much in your water. The reason people don't change water during a cycle is to make the beneficial bacteria stronger. It's like recharging a new phone. You are supposed to not charge the battery until it completely dies out. As well as tools. The reason being that the life lasts longer if you let them run thier course versus a "quick fix"

But looks to me as though you are through with your cycle, especially if you already have fish and crabs in there. But if your nitrates do not go down you may need to do more than a 5gallon change. I would purchase one of those 27gallon long rubbermaid with a lid from home depot. Just to have around. The 5 gallons are great for top off water, to be ready and waiting daily. But for bigger changes you want to have all areas covered.

Oh, and also, if you want your salinity to staythe same, just match your top off bucket with the desired salinity. I.E mine was at 1.021 and I wanted it at 1.024. So every day I top off with 1.024 and it raises about a point every 4 days. Which is a sloooow increase but much safer. It allows more time for the salt to dissinegrate into the top off buckets better. Never put salt in without letting it dissolve overnight or it will burn your fishies, like an open wound for humans..ouch

 

I believe my cycle is finished as well. I only did water quality checks once a week. So 2 total so far. The LFS guy said the LR and sand was crawling with the good bacteria. He thought I should change water in 2 weeks, which is this Thursday. I thought I would let him know what is going on tomorrow. You know some people think there shouldn't be any WCs. Starting Up can be confusing.

 

I haven't done a water change in my 75g but have in the 10 because the tank was neglected and full of tap water and nitrates. So tonight should be my last change unless it NEEDS to lower params in the future.

So, you DO have a few fish and crabs in there already?

 

Yeah to Chromis and 2 Hermits. The LFS guy said the ammonia from there waste would complete the cycle. Plus it was kick started with all that bacteria. I've had no problems. Fish and crabs are very active and happy, IMO. Talked to LFS today and we agreed I will do a 5 gallon change on the 2 week day, if Nitrates continue to climb. So fingers crossed.