Is a prefilter necessary for an overflow box?

Samcorp

New member
I do not want to use a prefilter for my overflow box for 2 reasons:

A) It causes nitrates and other bad things to build up.

B) Washing my used one will be a pain.

Is a prefilter necessary? Is there something better than just using a "sponge?"

Thanks,

Sam
 

Shane Hoffman

New member
I believe its necessary if you dont have a filter sock where the water enters the sump.....you will be amazed at how much that prefilter catches. Also you run the risk of those bits eventually clogging the line to the sump.
 

rupes reef

New member
I dont run one on my CPR over flow anymore, it got to dirty to keep up with. My theory on them is that they are the same as an overflow on a RR tank. The big difference is how the water gets into the overflow section. I would recoment using a filter sock on the overflow into the sump but as for the prefilter i personaly dont use them and have had no problems.
 

coral_lagoon

Pushrod Powered
I dont run any prefilters. Every 2 weeks or so Ill vacum up all of sediment/junk at the bottem of my sump. Using one of those Python gravel vacs. You know the one that you hook up to the kitchen faucet sump minus the big vacum tube attachement. With that said, my sump is always spotless..
 

Samcorp

New member
Coral, I mean the prefilters for the overflow boxes (external). They are the "sponge type" things that hook up onto the bulkhead.

Shane, if there is so much that is caught by the prefilter then couldn't that eventually clog too, and slowly it will make the flow go down?
 

coral_lagoon

Pushrod Powered
<a href=showthread.php?s=&postid=15417007#post15417007 target=_blank>Originally posted</a> by Samcorp
Coral, I mean the prefilters for the overflow boxes (external). They are the "sponge type" things that hook up onto the bulkhead.

I know, I have a CPR overflow box on my 60 reef. Dont use the pre-filter..
 

Shane Hoffman

New member
Yes the filter sock can eventually get clogged...but it would take forever. The bottom of the sock is the first to plug up. Then the debris slowly builds up on sides. Most socks are 8 to 10 inches tall so it would take months to completely fill it or clog it......My preference is to contain the debris and not let it float into my sump. I dont want it clogging up the intake to my skimmer or reactors or my UV sterilizer which all draw out of sump.
 

OneReef

Reef Guru
<a href=showthread.php?s=&postid=15418304#post15418304 target=_blank>Originally posted</a> by Shane Hoffman
Yes the filter sock can eventually get clogged...but it would take forever.


Thats odd that your takes so long to clog. Mine clog in a little over a week if I don't change it. Will start overflowing at less than 2 weeks. I try to change mine every few days.
 

Shane Hoffman

New member
I also have the prefilter on my overflow box...(which I rinse every 3 to 5 days) without that I am guessing I would be changing my filter sock quite often......
 

Lightsluvr

Tangaroa to 500 gallons
Premium Member
<a href=showthread.php?s=&postid=15418304#post15418304 target=_blank>Originally posted</a> by Shane Hoffman
Yes the filter sock can eventually get clogged...but it would take forever. The bottom of the sock is the first to plug up. Then the debris slowly builds up on sides. Most socks are 8 to 10 inches tall so it would take months to completely fill it or clog it......My preference is to contain the debris and not let it float into my sump. I dont want it clogging up the intake to my skimmer or reactors or my UV sterilizer which all draw out of sump.

Maybe I misunderstood...

Does this mean you only change your filter socks when they clog up?

What are your nitrates and phosphates running?

I change six filter socks twice weekly...

LL
 

Reef Bass

colors and textures
I use no sediment prefilter on my CPR overflow. Occasionally I'll run the water going into the sump through a filter sock when I'm stirring stuff up / rearranging things.

The rate at which filter socks clog is related to the pore size and detritus level. I can clog my 100 micron sock in a day if I'm aquascaping. My 200 micron sock would take days to fill up.

Also, keep in mind that the detritus accumulating in your sock or prefilter is going to be decomposing and can become a source of nitrates, having a negative impact on water quality.
 

Shane Hoffman

New member
Yes I only change my filter sock when the bottom is clogged. I pry should change it sooner but I personally dont have an issue with nitrates (always 0-10). I run phosphate and nitrate remover.
 

SC Trojan

New member
Does any one here know after how many days it usually takes for the detritus and other debri to break down and start releasing nitrates back into your water. I change mine out about every 3-4 days and was just curious as to when that starts taking place.Thanks.
 

Nanz

Premium Member
This is what my friend built on his 55 overflow box. He used the stockman style overflow and did not use the sponge that came with it. He does use filter socks and replaces them every other day.

http://www.randystacye.com/dursostandpipe.htm

overflow3.gif
 
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