View Full Version : Over Skimming?

03/27/2006, 12:27 AM
I was trying to find out if you can "OVERSKIM" your tanks?

If I bought a Aqua C 400 Rated Skimmer, Is that too much for a 100 gallon tank? Or will it be really clean?

Has anyone used Diatom Filters?


03/27/2006, 12:47 AM
Some marine biologists would argue that any skimming is merely taking food away from the corals, even just a little, as most of the proteins collected by a skimmer are used as food by corals and other organisms. For others, the more sterile the water, the better. In my opinion, you can skim a tank sterile to the point where phytoplankton and pods vanish. This is seen as bad by most, but for some who prefer to feed manually, it doesnt matter as much. I prefer to undersize a skimmer (or go with the mfg suggested capacity), but with a really good skimmer...small, but effective. This way, you wont skim all the water as fast, but what you do will be that much better. Skimmers can react and neutralize many reef ions, like iodine, which upon exposure to air becomes useless to corals...and then others would claim there is no such thing as overskimming and run such large skimmers that they should just put their corals in the skimmer with a light on top.

I have a couple diatom filters. I bought them for when I was breeding african cichlids, to clear up cloudy/bacteria bloom water. They work great, but I rarely use them on the reef. Last time I used it was on a friends tank who was cycling his tank and had a bacteria bloom before he could hook up his skimmer.

Roland Jacques
03/27/2006, 08:17 AM
a aqua c 400 requires a lot of pump (pressure) to run it properly. make sure you use the right size pump with it.

it wont make your tank "cleaner" just the water that goes though it. make sure you have a lot of flow in your tank and that well help your skimmer do its job better.

03/27/2006, 10:06 AM
Alot of flow in the tank does inprove the effectiveness of live rock and bacteria within the tank, but a low-flow overflow & sump are shown to improve skimming because the water at the top layers of the tank are the most protein rich.

Roland Jacques
03/27/2006, 11:04 AM
what is a low flow overflow, is that low turnovers of the tank?

i was thinking about high tank flow also keeping the detritus suspended better .


03/27/2006, 11:09 AM
yup...your return pump will only put back in display the amount that drains....3x-5x display tank's volume for gph of return pump is a general rule of thumb taught to me. so in NANO's case, i'd recc. no bigger than say a Mag7 for return pump.
-Just my 2 cents:)

Roland Jacques
03/27/2006, 12:14 PM
i guess i should have said your "IN" Tank water flow very high like 10xs min well allow your skimmer to work best.

03/27/2006, 12:51 PM
Sure. I hear you on the detritus suspension...thats perhaps the only argument I have heard for using a more flow through the sump...but then again, having a mechanical filter plumbed into a closed loop or something similar is just as good.

But when you lower the throughput of the sump & overflow, lets say to 2x the tank volume per hour, you target the upper most layers of the display tank where proteins tend to build up anyways. You can then direct feed this overflow water into a skimmer (recirculating design) and this allows for better proetin extraction than with a sump that runs, say...1000gph though the overflows and sump (as well as uses less electricity for the sump return pump, lowers that pump's heat transfer to the tank, and means less noise in the drainpipes to deal with).

Roland Jacques
03/27/2006, 04:20 PM
i agree with hahn. so NANOnewguy as you can tell we like recirc NW skimmers so that you can flow all or most of your overflow water thorugh your skimmer.

03/27/2006, 04:48 PM
<a href=showthread.php?s=&postid=7049581#post7049581 target=_blank>Originally posted</a> by NANOnewguy
I was trying to find out if you can "OVERSKIM" your tanks?

If I bought a Aqua C 400 Rated Skimmer, Is that too much for a 100 gallon tank? Or will it be really clean?

Has anyone used Diatom Filters?

If it were my tank that is the skimmer I would use. You could get away with a AquaC EV240 but the 400 is a beast. You will have fantastic water quality. Energy consumption is not that bad with certain pumps. The Mag 24 on that skimmer only draws 125-130 watts. People will disagree but that is what it consumes with the added head pressure of the injector. This has been verified by Aqua C and confirmed in the skimmer test that o2manyfish did a while back. With that skimmer it won't mater whether you have high or low flow through the sump since the skimmer will see approx 1600 gph going through it.

03/27/2006, 04:53 PM
I guess it depends on what you want to keep. For SPS, there is not such thing as overskimming. For LPS or soft corals, you can skim less, but most will do quite well in a low-nutrient system. It's always possible to add food if you need to...and really hard to take it out if you don't have a big enough skimmer.

Roland Jacques
03/27/2006, 06:05 PM
you have a good point. but your numbers seem wrong. i cant see how the aqua c 400 will have 1600 gph going through it. i dont have one but i have a aqua c EVC1000 and it does not flow that much (close but not quite) at a 16 psi on it.

BLockamon i pm you


03/27/2006, 06:24 PM
I don't think you can really skim too much
When you think about your tank setup, annd the volume of water that goes to the sump - there is still a lot left in the tank

I have a 230g setup & my skimmer is rated for 400g
I can tell you I have plenty of "stuff" still in my tank, and my corals do great
Mix reef of softies, LPS & Cap

03/27/2006, 07:20 PM
How does a Mag24 with all that back-pressure on it only use 125-130 watts?!?! It should be double that.

03/27/2006, 08:13 PM
You can never Over Skim.

dustin Combs
03/27/2006, 08:21 PM
We have a skimmer that is rated for 750gl on 220 gal of water.

03/28/2006, 04:51 PM
The TOM for January used a Deltec AP902 (rated for 480 gal heavy stocking) on a 90. He now uses an AP1004 (rated for 1200 gal heavy stocking). If that isn't overskimming, nothing is.

03/29/2006, 12:13 AM
Yeah I also don't think that you can overskim a tank, I've used small hang on the back and now I have a DIY Recirc skimmer and I get a lot better growth and color from all over my corals (SPS, LPS, etc..). I'm in the process of building a 120G tank and the skimmer I built would handle 300g without a problem.


03/29/2006, 11:02 AM

There is an article that states that you can overskim. Heck, like I said before, there are many who believe skimming in itself is bad for a reef, as most of what it removes is processed by LR, the SB, etc...and corals as food. I myself can see how a larger tank with a low bioload doesnt even need a skimmer, but there are many out there that put just as many fish in their tanks as corals and I would say that the skimmer is needed to fight the effects of overcrowding.

I think that there is no 'one answer for all tanks'. Its like the old DSB vs BB debate. There is no one solution.

I would also like to point out that it depends on the tank's inhabitants, not just size and amount of fish. A nano hardly has a use for a skimmer...its just easier to do a water change. And lets say you have a SPS tank...ok, it is prolly a good idea to skim to keep the water clear...but if you are doing a softy tank...tree corals, GSP, shrooms, leathers, xenia, clove polyps, LPS etc...then a skimmer is hardly a benefit, as many of those corals not only feed on organic chemicals in the water, but also the detritus in the system...that a skimmer would work against you.

03/29/2006, 11:29 AM
I base my opinions on other successful tanks that I have seen. If you look Steve Weasts (www.oregonreef.com) tank he has a mixture of SPS, LPS, and softys with very heavy skimming and filtration. His tank is over 800 gallons and his skimmer is rated for twice that amount, plus he is running heavy UV on it. But somehow the tank is very successful and colorful. As others have pointed out look at some of the tanks of the month, they have skimmers rated for a lot larger tanks.

Its hard to argue with their success.

Roland Jacques
03/29/2006, 12:02 PM
Their is also many successful no skimmer tanks. So I guess success can argue with success. Like Hahn said "I think that there is no 'one answer for all tanks'. But it sure is easier to add supplements to a tank that is over skimmed than to take out organics,... of a under skimmed tank.

03/29/2006, 03:24 PM
<a href=showthread.php?s=&postid=7068073#post7068073 target=_blank>Originally posted</a> by hahnmeister

There is an article that states that you can overskim.

I can find an article on reefkeeping stating pretty much anything.

AS to the mag power draw, pumps use less power the more pressure you put on them, not more. They move less water, so they use less power.

I still think there are much better pumps for the job though.

03/29/2006, 03:42 PM
Posting in the wrong thread Rich? Were not talking about pumps here...

Thats true, you can find many diverse opinions on methods of keeping here. Skimming may be a good thing, or a bad thing...depends on who you ask and how the system is set up.

03/29/2006, 07:55 PM
Just overskim and overfeed.

I'm planning a 250g rated skimmer on my 125. But I will have a medium to heavy bioload and feed phytoplankton more often. Because I know I'll have a large enough skimmer to handle extra nutrients. IMO you need as much live rock, sand, and skimming to remove as much nutrients as possible. You just replace those nutrients when you do a small water change weekly, or when you feed or add supliments. .