ASM Skimmer---Recirculating questions

[110galreef]

OK I plan to make my G3 a recirculating skimmer. The pump on it is a SEDRA 5000 (~500gph). My sump return pump is about 500 GPH and my tank is 110 gallons.

Ok so I plan to feed my skimmer with water pulled from the sump passed through the UV and then into the skimmer

So what would be an ideal flow rate here. The UV is 18w turbo twist w/ a recommended 200-400gph flow rate?

Would like 250gph be ideal for a 2x tank turnover rate?? Or go higher??

Also considering throwing my chiller inline as well? Good bad idea......it has about 300-400 gph rating as well?

Trying to use the least pumps and power needed!

[tashier]

I'm following along on this one. I have a G3 on the way, should be here today.

[110galreef]

Cool...Maybe I will post some pics for ya!

The best utilization of a UV is to skim the dead stuff right away, bvefore floating it back to the tank! Plus with a recirc mod I need to feed the skimmer so this sounds like a great plan.

Just not sure on ideal flow for the recirc mod. They recomend the MJ1200 which is like 295 gph......

[drdude05]

Feed your skimmer directly from your tanks overflow ... or from a designated skimmer chamber in your sump. Make sure that your skimmer gets first crack at the dirty water from your tank and then run the water through your UV sterilzer and chiller ... mostly to allow the skimmer to remove as much junk as possible befoe passing the water through any other equipment. It will decrease the rapididy with which detritus builds up in your UV sterlizer and chiller.

[tashier]

I thought about feeding mine with the return directly into the skimmer. There's just some things that bother me with the concept of low GPH through the sump. Even if you have a ton of flow stirring up stuff in the tank if you don't have enough flowing going down your overflow how is it ever going to make it to your sump?

I also raised the question in another thread of how can you actually measure the effectiveness of your skimmer other than saying 'gee that looks like a lot of skimmate'. Can the water be tested? I didn't really get an answer.

I'd like to do the recirc mod if I knew it actually proved effective. It would be nice to just run the return directly into the skimmer to save on pumps and power.

Edit: To add to this thought, I saw a post somewhere of someone who had added a recirc mod and said they didn't really see any difference.

[drdude05]

As for flow rate, I've always been told you want to skim your total tank volume at least once per hour. I personally am running a MJ 1200 as a feed pump for my ASM G4X. I then use the gate valve mod to regulate the outflow from the skimmer.

[110galreef]

Well the overflow is too much for the skimmer....thought about this already, just don't want to go T'ing and BV'ing to make it work!

The pump feeding the skimmer will draw water as it empties into the sump chamber housing the skimmer now! So it will be sucking water just skimmed from overflow anyway.

[110galreef]

Originally Posted by tashier

It would be nice to just run the return directly into the skimmer to save on pumps and power.

Hence my plan as I need to power flow through the UV and it is ideal to skim the dead stuff from the UV right away!

[drdude05]

tashier: I ran my G4X both before and after the recirc mod and I can tell a huge difference. After the mod, the skimmate is greener, smellier, nastier looking, and the collection cup fills quicker. The corals look healither too.

[drdude05]

The only problem I can see with feeding the skimmer via the UV system is if the UV requires a faster flow to be effective than the skimmer i.e. to get your UV to work optimally you need to speed up the flow which might cause too fast a flow through the skimmer and lessen contact time ... or vise versa.

[tashier]

The details and mechanics of skimming seem so vague IMO. I mean how do they get the ratings they give on skimmers anyhow? Example: The ASM G1-X has a 350gph pump on it, ASM rates it for 150 gallon while experts rate it at less than 100. The Precision Marine ES-100 skimmer uses a 700GPH pump but is only rated for 100gallon tank. If you're supposed to skim your water 1x per hour, wouldn't you be able to run a 700 gallon tank with the ES-100? It's all so confusing IMO. I've posed these questions elsewhere and didn't get any answers.

[tashier]

Originally Posted by drdude05

tashier: I ran my G4X both before and after the recirc mod and I can tell a huge difference. After the mod, the skimmate is greener, smellier, nastier looking, and the collection cup fills quicker. The corals look healither too.

What's your total water volume?

[drdude05]

You probably didn't get much response because the answers vary. They depend on skimmer design, pump output, venturi effiency, tank bioload etc. Really, you can only use the ratings on skimmers as a ballpark to get you started. Example, a skimmer rated for a 100 gallon tank might work on a 150 that has very light stocking with small fish that don't produce much waste and is bare bottom. But it may only be adequate for a 70 gallon volume if it is heavly stocked with corals, has a sand bed, or has fish that produce more waste.

The rule of thumb I use is I buy the biggest skimmer I can fit and assume it will only run a tank half the volume it is rated for. This may be simplistic. but I haven't gotten in trouble with my skimmers being too small.

[drdude05]

Total water volume with sump is 240 gallons.

[tashier]

Good point, there are a lot of variables to consider. Still, is there anything you can test your water coming out of your skimmer for to measure the performance of your skimmer. TDS or anything? We seem to be able to measure everything else, how well our RO/DI works, phosphate removers, light PAR, but no way to check the skimmer performance. I feel like anytime you can't verify something you are subject to just a lot of opinions and sales pitches.