Am I too late???
This may be way too late, but I was "perusing" and came across this.
I'm in a crunch to catch some shut-eye, but wanted to briefly chime in as to CC being "as effective." Crushed coral is not as effective, given the practical usage of it as a substrate. This is because there is simply too much aerobic bacteria churning out nitrates in the upper levels of the CC. In other words, the crud collects in the upper levels of the CC where there is oxygenated water, and thus there is not a complete breakdown of the nitrates into gas. Rather, the crud (simply stated) just decays and we have what is known as a "nitrate factory."
We have seen that with sand this is not the case. This is for the very simple reason of granule size. It is not that "crushed coral is bad," it is that the diameter of the average granule is WAY larger than that of sand, and so we don't have the "compacting" ratio with CC that we do with sand. We need anaerobic bacteria to break the nitrates into a gas. We get this anaerobic bacteria readily with a sandbed, but again, it's simply not practical with crushed coral. A good friend, Rob Toonen achieved a "balance" (by this, I mean a good biological filtration setup) but I believe it was with a depth of 22 INCHES of crushed coral. This is what I mean by "not practical." And this does not mean that if we simply had a 22" CC substrate it would "work." The crud (waste) needs to get drawn down into the anaerobic layers to get processed. If we don't have anything to accomplish that, again - we'd just have crud being churned into nitrates and released into the water column. The decay must be processed by anaerobic bacteria to transform into a nitrate gas wherein the ultimate "by-product" can be released via the gaseous exchange at the surface of the tank.
When this doesn't happen, we have one major nitrate factory. There are precious few people around who will remember me "trying" to make the crushed coral substrate work... I was applying the whole "grain-size-ratio" concept - but it just wasn't working. When I was jawing about this with Rob at one of the marine conferences out here he told me about the 22" substrate that was "successful." Again, how practical is THAT for most of us?
Anyway, I tried for about a year and a half when sandbeds were leading the cutting edge into biological filtration, and I no doubt marked some of the highest nitrate readings possible. Indeed, it was often joked that there were no test kits to MEASURE my nitrates, as I was always rapidly off the charts. Dale will remember!! This was not bad, though, because it helped lend some "real-time" credence to the issues of nitrates being "bad" for our tanks. There's nothing like actual experience to answer that question, and I never lost a fish! But nitrates are usually an indication that most corals/inverts will not fare well in such a system. I can not attest with any credibility on this issue, because my lighting was no doubt insufficient - and so I couldn't isolate any one cause as culprit for my "non-coral" environment at the time.
Anyway, we made the switch to Carib Sea's "Special Grade" reef sand... As Ron Shimek has aptly called it... wonder grunge A pretty big "swap" and nitrates were screaming back in no time. That was it... That was the time for REAL SAND!!!! And so it was that with no other change than a sandbed swap, the crazy nitrate problem was put to rest. Sure, the swap can be a pain, but I did an article which has helped a few folks out with the whole process - and a step-by-step makes it far less painful. It was a real learning experience, but hopefully I helped address the issue of a crushed coral substrate being as effective.
In summation, there are many ways to deal with nitrates, but there's no doubt that the most convenient way is to do so naturally, without the need/maintenance of mechanical filtration. What other filter allows us to be so "hands-off"? Most nitrate-processing mechanical filters have mediums which must be maintained/cleaned/changed. Sandbeds can go go go!!! There were a few reports of a "sandbed exodus" because a few people experienced disasters in their tanks. I can tell you, and I'm sure anyone with a degree of self-ponderance can concur, that if sandbeds were "time-bombs" then they'd be time-bombs for everyone. We've had sandbeds processing nutrients ranging from heavy bioloads to minimal.. and there are many on record spanning well over a decade - some have reached 22 years!!!
Anyway, I was probably one of the last of the "old school" to convert to sandbeds from a mantra of "crushed coral," and I dare say I'll be one of the staunchest supporters, having definitely learned the hard way!!!! But it was a great learning experience.... Hopefully I passed some on!!! Cheers, and hi to all... (been a while, huh? )
This may be way too late, but I was "perusing" and came across this.
I'm in a crunch to catch some shut-eye, but wanted to briefly chime in as to CC being "as effective." Crushed coral is not as effective, given the practical usage of it as a substrate. This is because there is simply too much aerobic bacteria churning out nitrates in the upper levels of the CC. In other words, the crud collects in the upper levels of the CC where there is oxygenated water, and thus there is not a complete breakdown of the nitrates into gas. Rather, the crud (simply stated) just decays and we have what is known as a "nitrate factory."
We have seen that with sand this is not the case. This is for the very simple reason of granule size. It is not that "crushed coral is bad," it is that the diameter of the average granule is WAY larger than that of sand, and so we don't have the "compacting" ratio with CC that we do with sand. We need anaerobic bacteria to break the nitrates into a gas. We get this anaerobic bacteria readily with a sandbed, but again, it's simply not practical with crushed coral. A good friend, Rob Toonen achieved a "balance" (by this, I mean a good biological filtration setup) but I believe it was with a depth of 22 INCHES of crushed coral.
This is what I mean by "not practical." And this does not mean that if we simply had a 22" CC substrate it would "work." The crud (waste) needs to get drawn down into the anaerobic layers to get processed. If we don't have anything to accomplish that, again - we'd just have crud being churned into nitrates and released into the water column. The decay must be processed by anaerobic bacteria to transform into a nitrate gas wherein the ultimate "by-product" can be released via the gaseous exchange at the surface of the tank.When this doesn't happen, we have one major nitrate factory. There are precious few people around who will remember me "trying" to make the crushed coral substrate work... I was applying the whole "grain-size-ratio" concept - but it just wasn't working. When I was jawing about this with Rob at one of the marine conferences out here he told me about the 22" substrate that was "successful." Again, how practical is THAT for most of us?
Anyway, I tried for about a year and a half when sandbeds were leading the cutting edge into biological filtration, and I no doubt marked some of the highest nitrate readings possible.
Indeed, it was often joked that there were no test kits to MEASURE my nitrates, as I was always rapidly off the charts. Dale will remember!! This was not bad, though, because it helped lend some "real-time" credence to the issues of nitrates being "bad" for our tanks. There's nothing like actual experience to answer that question, and I never lost a fish! But nitrates are usually an indication that most corals/inverts will not fare well in such a system. I can not attest with any credibility on this issue, because my lighting was no doubt insufficient - and so I couldn't isolate any one cause as culprit for my "non-coral" environment at the time. Anyway, we made the switch to Carib Sea's "Special Grade" reef sand... As Ron Shimek has aptly called it... wonder grunge A pretty big "swap" and nitrates were screaming back in no time. That was it... That was the time for REAL SAND!!!!
And so it was that with no other change than a sandbed swap, the crazy nitrate problem was put to rest. Sure, the swap can be a pain, but I did an article which has helped a few folks out with the whole process - and a step-by-step makes it far less painful. It was a real learning experience, but hopefully I helped address the issue of a crushed coral substrate being as effective. In summation, there are many ways to deal with nitrates, but there's no doubt that the most convenient way is to do so naturally, without the need/maintenance of mechanical filtration. What other filter allows us to be so "hands-off"? Most nitrate-processing mechanical filters have mediums which must be maintained/cleaned/changed. Sandbeds can go go go!!!
There were a few reports of a "sandbed exodus" because a few people experienced disasters in their tanks. I can tell you, and I'm sure anyone with a degree of self-ponderance can concur, that if sandbeds were "time-bombs" then they'd be time-bombs for everyone. We've had sandbeds processing nutrients ranging from heavy bioloads to minimal.. and there are many on record spanning well over a decade - some have reached 22 years!!! Anyway, I was probably one of the last of the "old school" to convert to sandbeds from a mantra of "crushed coral," and I dare say I'll be one of the staunchest supporters, having definitely learned the hard way!!!! But it was a great learning experience.... Hopefully I passed some on!!! Cheers, and hi to all... (been a while, huh?
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