Water changes during cycle?

I have a 29 gallon tank on day 8 of its cycle. I have 40 lbs of live sand and around 65 lbs of LR. All I see in the tank as far as algae is some soft flaky looking stuff hanging off some of my rock, powerhead, and filter outlet/inlet. The rest of the tank looks pretty clean. My question is, do I need to be performing water changes already, even though my tank has not yet fully cycled? Also, how much water should I change, and how often? Thanks in advance.

 

65 lbs of rock in a 29g tank? that thing must be stuffed full!

Don't do water changes until the cyel is complete, otherwise you will only inhibit the process and only make it take longer. Hopefully you do not have any filtration running at this time either. Typically, it will take 6-8 weeks to cycle on its own you may ad 1 raw shrimp to the tank if you are not already getting an ammonia reading in your tests). You should be tetsing your ammonia, nitrite, and nitrate levels. Each will spike and then drop.

Once the cycle is complete (ammonia/nitrite should read 0ppm, nitrate should be 5-10ppm), I would suggest doing 10% weekly water changes.

 

Did you add an ammonia source? What are the parameters? You should not do a water change until your ammonia and nitrite have spiked and then dropped to zero.

 

40 pounds of sand and 65 pounds of live rock in a 29 gallon? do you have any water to cycle with? but yeah, not wc's till cycle end!

 

Water changes during a cycle are o.k. For years now I've seen this debate come up and the side that argues for the "no water change until cycle is over" are wrong. And I'll prove why.

The worst argument is that when water is taken from the cycling system bacteria are removed and you are essentially taking a step backward. Some bacteria are removed during a water change at any point in a tanks life but they are not free swimming organisms and colonize hard substrates (rock, sand, filter pads etc.) This argument is easy to disprove.

The most common argument is that when a water change is done you are essentially removing the food required for the bacterial colony to grow. This is so wrong it makes me laugh every time I read someone who believes it. And here is why.

For your test kit to detect any ammonia you first have to have a source. So for the sake of this we'll say you are cycling with a raw table shrimp.
The shrimp begins to decay and ammonia is created. To combat the ammonia you must have introduced bacteria in one way or another, your bio-filter. So lets say your rock is fully cured and has at least some beneficial bacteria beginning to colonize it.
So your shrimp is rotting and ammonia is produced. After day 1 you get a reading of 1.0ppm, the next day your reading is 2.9 and the next day the ammonia is at 5.0 by the end of the week the ammonia in ppm is into the double digits and nitrites aren't even showing on the tests yet. Is it o.k. to do a water change? Yes. Because the increase in ammonia only proves that production is greater than consumption. Meaning the decaying shrimp is producing a lot more ammonia than your growing bacteria can possibly consume. By doing a water change of up to 50% each week you leave plenty of "food" for your growing colony of bacteria and are getting into the habit of routine maintenance.
When the day comes that you test and the results are 0 for ammonia even though there is a form of production in the tank (rotting shrimp, pooping fish, etc.) then you'll know that consumption by the bacteria is equal to or greater than production.
This is why that it's essential to add fish slowly after the cycle is complete. One or two fish per week cannot produce enough waste to create more ammonia than the bacteria can handle and will give the colony time to grow larger to handle the increase in bioload.

 

I see what you are saying. Yes the bacteria does colonize on surfaces, but I would argue that ammonia is dissolved in the water first before the bacteria can get to it in order to break it down. If you change out some water, which the ammonia is in, then you would be prolonging the cycle. If what you are saying is that the ammonia is not in the water itself, then how could you test for it. The ammonia, nitrite, nitrates or whatever are broken down by the beneficial bacteria as the water flows over the surfaces that the bacteria is inhabiting.

 

I guess my question would be, is, if you're not using live critters to cycle, then why would you waste your salt/DI/time etc on water changes during a cycle? seems like a waste of $ to me! Let it run its course and when the trades kick up, then wc to drop them! I may be wrong, just throwing it out there!

 

That is only part of what I said. Of course it you'd read both arguments completely you'd understand that.

If you get a reading of any amount of ammonia after doing a test THE ONLY THING THIS PROVES is that the colony isn't large enough to match production with consumption.

To remove all of the ammonia (food for the bacteria) you would have to remove all of the water. If you remove half the water and are still getting a reading of half the ppm you did before hand than there is still adequate food for the growing colony to consume. It's pretty simple really.
This is why a reading of ammonia in a cycled tank is such a serious deal. For some reason ammonia in amounts greater than our bio load could consume is being produced.

Even Fosters and Smith recommend a weekly 50% during the cycle and then 10 weekly afterwards.

 

I don't think that you need to use "live critters" to cycle with. I hear of many people using frozen shrimp to cycle with and pulling it out once is starts to dissolve. I agree with letting it run its course. I think that is the best way to build up your bacteria culture in your tank. I also think that you should let your nitrates drop to almost zero as well, unless for some reason they wont drop to where they need to be. Great point though. ;D

 

That isn't the question. The question posed is if it's o.k. to do it or not. It's fine and it doesn't change the timeline of the cycle in the least. As a matter of fact the only way to change the timeline is by introducing more beneficial bacteria than a rotting shrimp can produce. Like with products Dr. Tim puts out or NutraFin Cycle. In this case waterchanges are a no no because it's takes a while for the bottled bacteria to settle and begin colonizing. But will considerably speed the cycle up.

I personally don't use them and I will do a water change to dilute the rotton odor from the shrimp in the nylon.