Quote:
Originally Posted by gobytron
Reefwars, unless you can show me some documentation where all of a sudden water changes have gone from being great for nutrient export to poor to somehow poor, I'll have to chalk it up to your opinion.
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I think you guys are both right.
I have to
kind of agree with Denny, and I
kind of agree with you. It's not that water changes are a
poor nutrient export, it's just that water changes aren't usually the
most effective choice. Water changes for nutrient export in tanks that have a small bioload and are regularly maintained certainly may be the
best option. For most reef tanks though, there are often better options - especially if you're using a premium salt brand. This is particularly the case when nutrients have gotten out of hand and you're looking for nutrient export for the purpose of
nutrient reduction.
For example, I started doing maintenance on a reef tank with about 750 ppm nitrate and 2.5 ppm phosphate. I'm doing 10% water changes and added a biopellet reactor. We're down to about 500 ppm nitrate now. To further make this point, I recently added some dried out live rock to a tub with RO water. The tub had 100 ppm nitrate and almost 0.5 ppm phosphate.
Two 100% water changes later and I have noted ZERO difference in those nutrient numbers. Thankfully I can use RO for this instead of saltwater. If you translate that to the above mentioned tank with 750 ppm nitrate, I could have used 3 buckets of salt to do two 100% water changes and I'd still be at square one. I spend what is equal to 6 buckets of salt on a biopellet reactor and biopellets and I'm leaps and bounds ahead.
On the other hand, my own 50-gallon frag tank at home has a skimmer on it, but no other means of nutrient reduction (no carbon, no GFO, no resins) other than weekly 20% water changes. The tank isn't overstocked, but it's definitely full. The tank is maintained at 2-3 ppm nitrate and 0.08 ppm phosphate which is exactly where I want it.
SO my point is, every situation is different, and a nutrient export program needs to be chosen to
fit the needs of that particular tank and also
that tank's caretaker.
And here's a 12 year old RHF article to prove you ALL wrong because we knew this shizz a decade ago before we even had voodoo biopellets!
http://www.advancedaquarist.com/2003/8/chemistry