water change on cycling tank?

[Lynnmw1208]

So I was wondering how often to do water changes on a cycling tank? I almost just want to let it go for the bacteria to stabilize but I'm not sure. What did you guys do? I almost feel like I'm doing 1gallon water changes as it is adding so much RO/DI topoff from evaporation.:lolspin:

[peasofme]

no water changes

[drillsar]

is there any life you want to keep on the rocks? If not then let it run, doing water changes will prolong cycle

[Toddrtrex]

I have, and always will, do water changes when cycling -- even will have the skimmer running. I paid good money for the life on the live rock, and do not want an ammonia spike to kill off any of that life.

I just set up a 40 breeder and did weekly 5 gallon water changes, just like I do on all of my tanks.

[syrinx]

I run skimmer- but don`t do water changes. I want a full bacteria load to grow, and the more ammonia the more growth of bacteria. I agree with todd about doing it to limit dieoff- but in the old days with ricordia and polyp rock- it all went through the cycle no problem. Today much of the live rock is merely coraline rock and thus unaffected by ammonia.

[Toddrtrex]

Here is a good post about this, from this thread. (http://reefcentral.com/forums/showthread.php?p=12110142)

For a given bioload there's going to be a roughly set carrying capacity for the bacteria. Whether you do a waterchange or not, you're going to end up at the same place, you just change the path you take to get there and how long it takes.

If you don't do a WC you finish the initial cycle quicker but you overshoot the carrying capacity, so the population drops, overshooting it again. You end up setting up fluctuations in the population and prolonging the time it takes for the tank to "mature" or finally settle at the carrying capacity.

If you do WCs it takes a little bit longer for the bacteria to reach the carrying capacity, but there's very little overshoot so the tank is essentially mature as soon as the cycle is done. The fact that there's less ammonia also helps to preserve diversity on the liverock.

Here's a little graph to show what's going on.
http://i23.photobucket.com/albums/b383/msgprimate/cycle.jpg

Personally, I recommend doing WCs, but either way will work.

[syrinx]

Better off without that example-for many reasons. We had already stated both side of the coin without it.

[Toddrtrex]

So giving the OP as much info as possible is a bad thing? Just because you don't agree with it, doesn't mean the info shouldn't be shown.

But, sorry that me posting it bothered you so much, but I stand by it.

[anaya]

ok so if i do the wc during cycle what % are we talking? never cycled my tanks this way but then again i have never done a dsb till this tank either...

[sasharotty]

ok so if i do the wc during cycle what % are we talking? never cycled my tanks this way but then again i have never done a dsb till this tank either...

No more than 20%.

[Toddrtrex]

Can't speak about a DSD tank -- only had have (( or currently have )) shallow sandbed tanks. As for the water changes, I have always done 5 gallons -- since that is what I do with my active tanks, it is an easy amount for me, using old salt buckets.

[Lynnmw1208]

hmm ok I think I'll wait on a wc for right now. So far the only things that hitched a ride on my rock is a tiny snail and some baby brittle stars. they are all alive and eating so the cycle is probably not bothering them a whole lot.

amm is .5
nitrate 2.5 (i think, hard to tell between 0 and 5...)
nitrite .25

these haven't fluctuated very much and i've tested every other day. I'll prob do a small water change next week.

[jimmy frag]

regardles of the amount of bacteria levels you reach through the cycle of curing the live rock the bacteria level will drop as there will be nothing left to feed them when the cycle is complete. no load. bacteria levels will only rise again as the load increases

[anaya]

Thanks looks like it will be 5gal then

[Angel*Fish]

Here is a good post about this, from this thread. (http://reefcentral.com/forums/showthread.php?p=12110142)
http://i23.photobucket.com/albums/b383/msgprimate/cycle.jpg
Nice! What would we do without Greenbean? The info on that chart is seriously the coolest new thing I've learned in a while. Thanks for posting that, Todd.

[jimmy frag]

why no more than 20% ? we are cycling rock. where did this figure come from

[Virtuoso]

Better off without that example-for many reasons. We had already stated both side of the coin without it.

Care to explain those reasons?

[Toddrtrex]

Nice! What would we do without Greenbean? The info on that chart is seriously the coolest new thing I've learned in a while. Thanks for posting that, Todd.

Sure thing. I am mad at myself for not bookmarking more of his posts/threads. Just when I think I know a lot about this hobby, I (re)read his posts and feel like a first year hobbyist.

[syrinx]

no data involved on graph- classic junk science. Of course I coud ask the 5 or more question needed to quantify what he is trying to say- but thats what the graph should do `eh? And as stated both ways work fine- sometimes one is better than the other-depends what end result desired is.

edit- this in no way is a statement about greenbeans work-I don`t know the original context of the discussion- or what the chart was intended to point out. I just feel here it lacks any data to be of real help. Mad respect for greenbean as a aquarist.

[Toddrtrex]

no data involved on graph- classic junk science. Of course I coud ask the 5 or more question needed to quantify what he is trying to say- but thats what the graph should do `eh? And as stated both ways work fine- sometimes one is better than the other-depends what end result desired is.

edit- this in no way is a statement about greenbeans work-I don`t know the original context of the discussion- or what the chart was intended to point out. I just feel here it lacks any data to be of real help. Mad respect for greenbean as a aquarist.

PM him about his "classic junk science"

I provided a link to the thread where that quote came from, which would provide the context.

[syrinx]

I am not going to continue this- I think he would agree that not having any data is not the way to prove anything. Perhaps I use the term junk science to easily- as i edited I ment no offense to him or his work as a whole. For the graph to mean anything there would need to be things like time as in units in days or weeks, population as in counts, baseline as in what load is being tested to. What is the initial dose or source of ammonia- is it a consistant or one time addition? Science is not about proving a hypothosis to be correct- its about finding out why it is flawed.

[steelhead77]

OK. All the petty arguments aside... IMO doing water changes during a cycle are a good thing for a couple reasons:

1) Bacteria does not inhabit the water. It inhabits the rock. If you have poison water, you will kill what's on the rock. Even tho you only see a few small snails and brittle stars, there is a plethora of beneficial life on the rock that will die in poison water and prolong your cycle.
2) You get used to maintaining your water quality (test at least every other day) while there is little to no chance of killing anything expensive if you do it wrong (other than the aforementioned plethora).

A 20% per week change is a good thing to do. However once established, never be afraid to do a 50% if your levels get "off the charts" i.e. Nitrates of 100. Remember, the soultion to pollution is dilution. It's always better to have your livestock swimming in fresh saltwater than poisoned dirty water. You will see an immediate change for the better when you do this.