View Full Version : t-4 velocity pumps

12/24/2006, 10:14 PM
what do you guys think about the t4 velocity pump?

12/25/2006, 03:37 AM
quiet will run hot, unless they have changed the impeller will get clogged easily, and begin to shred your incoming water turning it into a needle wheel skimmer efffect.. NOt what you want for closed loop.

Impeller is a strange bird on this pump, looks like a UFO disk with small sections where the water enters through "vents" its these vents that get clogged quickly and shred the water.

I found this out the hard way attaching one to my closed loop system. I though I had leaks in the plumbing.. Couldnt get rid of the MB for anything, even tried siliconing my joints.. After I dumped that T4 pump no more mb, I put a standard impeller type pump on it, worked perfect.

So I took apart the T4 and found debri in the impeller.. cleaned it up and put it back in, worked fine for a bit, no MB, then as the impeller clogged In minutes... MB were back.. Sold it for half of what I purchased it for.

Also they do generate HEAT because they have NO fan on them, the housing gets hot.

Other than that, they are fine.. hahah

12/25/2006, 06:42 AM
i had the mb problem with the close loop too it is a very quiet pump but mb and heat i would never buy one again

12/25/2006, 07:56 AM
I happen to like them. I ran one on my 180 as a return pump for about a year. I used a clip-on fan pointed at the wet end of the pump. Worked fine, had no heat issues.
I now have 3 Poseidon/Velocity pumps on my 240.
One is on a closed loop that goes to 2 sea-swirls. I have no micro-bubble problem. They have been running since August
They are absolutely the quietest pumps out there.
So people have problems with them and others don't.

12/25/2006, 08:00 AM
i didnt have problems untell about 1 year or 2 years after use.

12/25/2006, 09:26 AM
If you're getting Microbubbles from this pump, its because its cavitating, and your closed loop isnt set up correctly.

12/25/2006, 10:05 AM
Yeah I have to disagree with BubbleMonkey, I used the T4 for 2 yrs as a Closed loop pump and it worked awesome. Never had any problems with it clogging or bubbles, sounds like you had it setup wrong.

My issues with the pump is the amount of heat it puts into the tank and because of the heat it gets a lot of buildup on the parts. Also didn't really like the fact that you cannot hard plumb it.

12/25/2006, 10:18 AM
You can hard plumb it. The hose adaptors take flex PVC which you can attach any PVC fittings to.

12/25/2006, 10:21 AM
Anyway I'm looking for a good return pump around that much flow maybe a bit more, but don't have more than 200 dollars any suggestions?

12/25/2006, 11:16 AM
these are the best/quietest pumps that I have ever used. Presently I have one on my 90g reef (via OM Squirt) & another on my 260g FO. Totally silent & I have had zero issues with clogging, bubbles.... etc!

I have been using these pumps for over 8 years now again.... with zero issues

the bad side is the heat & if you are using it on a 180g I wouldn't worry about it :)

12/25/2006, 11:18 AM
well in the winter it will not be a problem but in the summer the house gets kept about 82 degrees old house no central ac, so I'm kinda worried about that.

12/25/2006, 12:20 PM
On a 180 gallon tank you should not have any problems and if you start to just through a small fan over the sump.

12/25/2006, 01:01 PM
Well nothing was setup wrong with the pump, or closed loop necessarly.. (see below about the strainer though) I have to clear some situations up about my setup however that I think are pertinent to my T4 getting clogged quickly.

As far as INTAKE having cavitation that aint correct either, I had 1.5" intake all the way to the pump... No air leaks in the intake plumbing, no increase in water movement due to restriction.. near intake...Nothing wrong with the plumbing.. At 1.5" it was not getting starved at all. (one main reason for cavitation)

Trust me I was forced to study up on that too, and did so, learned a whole lot more about cavitation that I ever wanted to.. but this knowledge was a good side effect of owning a T4 Pump for the time I did... I learned all about the all the different types of cavitation etc etc.. (backflow, impeller tip, bubble) and what causes each. In this case I think we are talking about impeller tip cavitation, not due the impeller (since the T4 really doesnt have any (besides the small vents) but rather the "impeller" became the debris that would stick out of the vents when they were clogged, were acting like mini shreader impellers :)

Ill look for the CAL TECH link I found, for those of you who have some time and are interested in the subject this was one of the best articles i have found on the topic. After all that it just turned out I was using a NW Pump on my closed loop! hehhe

Here it is.. drink some coffee then read it..


But for me switching the pump out fixed the problem never came back with ANY PUMPS I have used.. And I have never looked back.. Seeing the T4 work fine after cleaning for a few minutes, without MB, then start producing again after debris hit the impeller and clogged it, convinced me that this pump CANNOT work properly for any length of TIME when debris are abundant, without creating MB when those vents get clogged with debris. Sorry No one can tell me otherwise.. Debris turned MY T4 into a Needle Wheel impeller.. ahhaha So you can say my STRAINER was not setup properly above the substrate which is true, but it only sped up IMHO what would EVENTUALLY Happen to it anyways. For those of you who have it work, maybe you are good about cleaning it often.. which is good anyways.

Also, Maybe some of you dont have that problem for other reasons.. (strainer on intake, intake placed away from debris on bottom etc) Though you say it works for you im surprised that after a long time, debris dont get in there. Maybe thats why it worked for SOME a year or so, then after the impeller got clogged, dirty, ie...debris built up in the vents, the MB started. That would make sense. In my case the placement of the CL strainer probably RAPIDLY reduced the time for this to happen.

But, the debri in my case debris and sand could easily get in there due to my strainer being located fairly close to the substrate about 1" above the sand, fish could kick stuff up just by swimming by the strainer... I also turned the strainer horizontally under rocks sideways vs vertical, to hide the 1"x 6" strainer..(it was setup this way before I realized that it was too close to the sand)

But with all these factors, this same setup did NOT effect a standard impeller pump at all.

I wonder also if they changed the impeller design since I owned one about 3 years ago.. Anything is possible. The impeller I had was disc shaped with the vents.. For those of you who have had good experiences, what is the shape and type of impeller?


For those of you having no problems congratulations.. i however wouldnt take the chance.. as I have ALREADY had a bad experience with them.. IMHO, Go with a standard impeller pump of any kind that is "MEANT" for inline use and you will have success. Right now Im just running an Ocean Runner 3300 on my CL which aint the greatest for external inline use (the way they connect that volute is weak comes aprart too easily) I know its not really "meant" to run inline but it does and does it QUIETLY.

I used a Mag 9 on there for a long time, with no issues (another non recommended submersible pump) but I knew the housing on that pump could leak over time so I replaced it.

12/25/2006, 01:04 PM
<a href=showthread.php?s=&postid=8824665#post8824665 target=_blank>Originally posted</a> by stdreb27
well in the winter it will not be a problem but in the summer the house gets kept about 82 degrees old house no central ac, so I'm kinda worried about that.

The thing is, any pump that is internal or external pump will increase the tanks temp. Some are add more or less & usually external pumps with fans are louder then pumps w/o the fan.

I really doubt you would have much of a change in temp & like others states, throw a cooling fan on the pump :)

However, my next external pump will probably be the snapper fro sequence. I have been so impressed with their pumps that this little guy has me intrigued. The larger brother the Dart is pretty quiet thus I feel/hope the snapper will only be better :)I beleive iot has a fan & the only bad woulf be it flows around twice what the T4 does.

12/25/2006, 01:48 PM
<a href=showthread.php?s=&postid=8824010#post8824010 target=_blank>Originally posted</a> by steve414
i didnt have problems untell about 1 year or 2 years after use.

Curious did you clean it often or at all during that year? If not, That would make sense to me that a NORMAL Setup would get debris and clogg over time....just by running it, no matter what..

Also after a year or so when it gave you "problems" what kind of problems did you have.. MB?

When it started, Did you try and clean the impeller, and then reinstall the pump? Probably would have worke fine again for awhile.. then started up again IMHO.

In my case everything was sped up due to the strainer, that was my OLD tank, however, In my new tank the strainer is in its OWN debri free unused overflow box. :) I learned my lesson about strainer placement.

12/25/2006, 02:50 PM
velocity T4 pumps are great. Ive had two running constantly for about a year and a half.Just clean it once and a while like anything else.As far as heat I have a chiller and dont notice it.hth