20% weekly W/C too much?

[jandree22]

I was recently advised that my 20%(14-15gal. new water, 75gal. tank) weekly water changes are too much shock to my system as far as the nitrogen cycle's concerned. It's pretty much a FOWLR system right now, 1 yellow tang, 2 clowns, 3 chromis...although I'll be doubling that amount within the next couple months.

I was told as little as 5% is what should be done. I'm running only a CPR BakPac 2R with a the airstone mod, so I figured going more heavily on the W/C's was kinda necessary. Any thoughts?

 

[Anonymous]

I agree that 20% weekly is too much...but if you're system needs it (because of high nitrogen or some other problem), there is no reason that a 20% change should "shock" your system if you match temp, SG, and pH of the water. It's just a pain in the ars to mix up that much water and do the change.


I, for one, haven't done a water change on my 72 gallon reef for going on three months now and the tank has never been healthier. I feel like Kramer in teh Seinfeld emisode where he runs the car after the gas light goes on, just to see how far it can go before it runs out of gas. I still haven't seen signs of a problem and my trates are under 5ppm, so I feel pretty good about not having to mix water and deal with changes.

 

[jandree22]

haha, I remember that episode! :lol:

Well, I guess maybe I'll bring it back to 10% or somethin... Shame on me for not checking the pH before I put it in, but I always let it mix at least 24hrs and the temp and salinity(checked with a refractometer) are always a dead-on match

 

[Anonymous]

I do 20% every month with good results. Fact this is about what was recomened in a past AA article.
http://www.advancedaquarist.com/issues/ ... /short.htm

Thought it was at least ineresting reading!

 

[Anonymous]

IMO:

1) weekly 10% WC's for small systems without adequate skimming.
2) monthly 20% WC's for medium sytems.
3) bi-monthly 30% WC's for large systems.

 

[jandree22]

ghostofmilz, interesting thoughts.... your basing that on the fact that larger systems are more stable I assume?

 

[Bobzarry]

3 years and counting



Bob

 

[Anonymous]

ghostofmilz, interesting thoughts.... your basing that on the fact that larger systems are more stable I assume?

Yea, more or less. Smaller systems can get out of balance pretty quickly. Large systems, on the other hand, tend to shift their parameters much more slowly. However, large systems require large % WC's to have much of an impact.

I also tend to beleive that smaller systems have limited capacity to achieve balance as more-or-less complete eco-system. Thus, they need more fine tuning and adjustments to keep them going. Big systems tend to settle into a stable eco-system more easily, and therefore only need periodic adjustments. It also helps that big systems generally have more diversity - something that is difficult to achieve in a small system.

For example, my 360 reef is pretty stable. I do a 30% WC every 3 months or so (sometimes less often - like Bob).

My 175 FOWLR gets a 20-25% WC monthly.

If I had a nano, I would change 5-10% of the water 1 or 2 times per week (particualrly if running skimmerless).

 

[Anonymous]

5% is fine. In a fish only or a FOWLR 20% would be okay, but it would be overkill. Just beware of overcrowding that tang. And remember that clowns will defend their territory.

 

[brahm]

..20% weekly isn't to much, that is fine. I some times do 20% twice a week, if you do enough water changes your tank parameters will stay close enough with the new salt water you replacing it with that it won't shock the system... Heck if could do 20% daily I would.

 

[Ben1]

3 years and counting



Bob

What makes your tank successful after 3 years of no wc? How do you then recommend on exporting nutriets then?

I do a 30 gallon bi-weekly water change on my 150 using RO/DI.


I dont think 20% every week is too much either. In fact when I do water changes on my 20 I usually do more like 50-70% and only do this once every month. Some times I do the 20 bi-weekly though. I also mix the saltwater in a trash can for 3 days befor doing this high change and balance the levels, most importantly IMO, temp. Of course the 20 id coral only right now and If I do this change with fish in the tank I would romove them first to a bowl and re-acclimate after the change.

 

[wstellwagen]

Craig bingham wrote an extensive peice on this in (Ibelieve) AF. The bottom line was small changes are basically worthless for correcting inbalances or reducing polution.A few moments thought about the effect of a 10 percent change on any problem makes this clear.

Terry S. should have an exact reference. Also note the dilution is even more reduced if one adds the new water and then removes excess

Walt

 

[Anonymous]

I have heard of quite a few folks who don't change water for years. Personally, I wouldn't wait that long. I change about 15%-20% every 2 to 3 months.

 

[Fastmarc]

If you are doing water changes with natural sea water, do it as often as you please. I think it is a lot trickier when mixing salt, so be careful.

 

[Anonymous]

I was recently advised that my 20%(14-15gal. new water, 75gal. tank) weekly water changes are too much shock to my system as far as the nitrogen cycle's concerned. It's pretty much a FOWLR system right now, 1 yellow tang, 2 clowns, 3 chromis...although I'll be doubling that amount within the next couple months.

I was told as little as 5% is what should be done. I'm running only a CPR BakPac 2R with a the airstone mod, so I figured going more heavily on the W/C's was kinda necessary. Any thoughts?

could you explain what they meant by that?


why/how on earth could/would water changes do anything to the nitrogen cycle?




fwiw -

water changes can be done in a frequency ranging from none, to 50% daily

either way, you'll get a nitrogen cycle, and you'll end up with the amount of bacteria your nutrient producers can provide for


if anything, regular water changes may actually HELP the establishment of all the various bacteria populations more quickly, by way of providing a healthier (less toxins) environment for all the critters in the system

establishing all the 'higher' links in the chain is also a requirement for a good varied, and functioning bacterial fauna :wink:

 

[Anonymous]

3 years and counting



Bob

What makes your tank successful after 3 years of no wc? How do you then recommend on exporting nutriets then?

I do a 30 gallon bi-weekly water change on my 150 using RO/DI.


I dont think 20% every week is too much either. In fact when I do water changes on my 20 I usually do more like 50-70% and only do this once every month. Some times I do the 20 bi-weekly though. I also mix the saltwater in a trash can for 3 days befor doing this high change and balance the levels, most importantly IMO, temp. Of course the 20 id coral only right now and If I do this change with fish in the tank I would romove them first to a bowl and re-acclimate after the change.

Three months so far in my 72 gallon and my trates have never exceeded 5ppm.

In fact, I have been WAY overfeeding lately to get some algae growing in the tank, since I have had ABSOLUTELY NO algae growth for some time and I want my tang to have some extra algae and my mandarin to get some more pods.

I can only assume that there is some kind of denitrification going in in my sand and rocks. Plus, I have a ton of bioballs in the overflow and in a wet dry. They are said to be nitrate factories, but when I set up my grow out system 4 months ago (two 40 gallon tanks plumbed together with a 40 gallon sump) I loaded the overflows of both tanks with bioballs and after the initial cycle ended, the trates were at 60ppm 8O ...I did absolutely nothing...not even a water change...and the trates have slowly gone down to under 10ppm on their own.


I can't say why I'm so lucky, but I won't look a gift horse in the mouth and as long as things stay this healthy, I'll be like bob and not do any changes at all.

 

[Anonymous]

20% each week will not hurt a darn thing, especially in a FOWLR. In fact, some heavily stocked FOWLR tanks need as much. For you though it's overkill.
For a reef I'd back off a bit. I do 20% a month.

Jim

 

[Anonymous]

Looky here for an article that shows the deminishing returns you get from multiple small water changes vs. a single large one.

This really doesn't answer the original question, but is a good read anyways.

Louey

 

[djtodd]

Granted, this is in my 100G FW tank, but I just top it up as needed. A nice big tank = good ecosystem, and it pretty much takes care of itself.

Now my 12G reef gets 10% every 5 days or so.

 

[Anonymous]

Unless it's a fully planted tank, freshwater tanks need far more water changes than reef tanks do. This is due to the fact that a freshwater tank does not have a mechanism to export nitrate. If you're keeping messy fish such as the larger cichlids, I gaurantee you that topping off will not suffice. I've had 180 gallon tanks that required 50% water changes weekly.

Jim