[Ratpack]

Before I go and drill my sump, just thought I would see what the pros and cons are of having an internal return pump verses one that is external via bulkhead. I know heat will be one, but what other factors are there and what do most prefer?

[charlie]

External, it is easier to do maintenance on. JMO

[FireEater]

I use two drop in Mags in my sump and I find that the maintenance is easy that way for me. Plus with internal, you do not have to worry about another bulkhead that may leak on you as well as fittings.

Drop in was plug and play so to speak. You can see them in my sump pics from the link in my sig. You can see when I added the first pump, then on the last pic on the right the second one was added about a year later.

Drop was perfect for me as I didn't have the room outside my sump to install pumps.

[Poseidon]

There are advantages to both, I have 2 external pumps running my return and skimmer. I have also used a pair of MAG12's internal before anf that worked easy too. I have to agree with Charlie about maintenance, a couple of ball valves and unions, and the external pumps are in my hand... The same can work for internal, but you get your hands wet!

[The R/C Man]

Also with an internal pump you have an electrical source in the water. Not that it happens often but there is a potential for shorts in the water. Internal pumps also transfer heat into the water so that could be a problem....

[scooterman]

How big is your tank?
I have a 125g tank with a centrifugal pump, It supplies water to the chiller also but comparable to a good submersible like & Eheim, they can be quieter, also heat from the big pump vrs little can be about the same, smaller returns will not add much noticeable heat. If you do use submersible, also use a GFCI to plug it into. It comes down to personal things to consider, like location, noise heat etc, also how much flow do you need. I don't consider sump return flow the same as main display internal flow, to me that should be separated for many reasons.

[golfish]

I'd opt for the external pump if its going to be a reef tank. There's something about Ca additives and internal pumps that just don't go together.

[charlie]

Originally Posted by golfish

I'd opt for the external pump if its going to be a reef tank. There's something about Ca additives and internal pumps that just don't go together.

Very good point

[The R/C Man]

Yes what Charlie said... :-)

I have actually experienced that when I overdosed Kalkwasser.....

[golfish]

Originally Posted by The R/C Man

Yes what Charlie said... :-)

I have actually experienced that when I overdosed Kalkwasser.....

Mix a Ca reactor along with a Kalk reactor and your cleaning these pumps once a week...

[scooterman]

What size sump are you going to use & is it glass or acrylic? Usually If you do over dose you will have problems but that leads to other problems as well, even external pumps should be cleaned in such a case (you will prematurely wear bearings If you calcify the impeller & it runs slightly out of balance), I don't find it much more difficult to do either way. If your using a small thin glass tank for the sump, I would not drill anything less than 3/8" thick as vibrations will/can shatter thin glass. That would be my first concern, otherwise It is all good either way.

[golfish]

Originally Posted by scooterman

I don't find it much more difficult to do either way. .

so I have to ask, are you running a Reef tank and what kind of Ca additives are you using? If your running internal pumps that are ceramic shafts on ceramic guides (must be if you have a 125) what are you doing to solve this problem?

[scooterman]

Actually my last tank I had a pump with ceramic shaft, when it got loud it was time to clean but the majority of the time it wasn't from the additives I used for maintaining ca & alk or Mg. After some time though it did need cleaning & I had to tear it down & soak it in muriatic acid or something like to clean it throughly, being careful not to break it. Right now I'm in the process of starting up a new reef so I have a reef tank with no reef yet & I use an External pump. I don't think I would ever need to clean out a pump weekly though even if your running a kalk & ca reactor, I must ask at what levels are you keeping to have build up problems that fast? BTW this tank I will be automation a two part dousing system.

[acer]

HI - just tagging along and enjoying the info- Don't mean to hijack - but I also find that using a internal pump in the sump/refugium takes up space and therefore, reduces the amount of live rock, media filters, or even water volume that you can have in the sump/refugium area. Therefore, if your have the room I opt for an external pump return setup.

[The R/C Man]

For my little tank with the internal pumps, I add a thin layer of 100% silicone grease to the shafts and other internal parts. This stretches out the cleaning time by months. When they do need to be cleaned the process is much much easier. They do not need to be soaked in vineger. Just cleaned with a brush.

Additives: For a while I was using both reactors (calcium and kalk) but that proved to be to much. A calcium reactor although it does add calcium also raises alkalinity. Maybe even more so than calcium. So a tank with a heavy calcium load usually needs both. Kalk has other benefits besides just raising calcium levels. It also helps to precipitate out some chemicals (phosphates I believe). There are other benifits as well however I need to go back to my books for reference as it slips my mind.

[scooterman]

Good points Greg. In the wild I've never seen a reef with as many different corals as we keep in your tanks but the corals that do grow are huge, measured in feet even. So in our reef tanks we tend to keep elbow room only & stock heavily which in turns creates the need to maintain CA. alk & Mg in balance. Using reactors has major benefits but over a long period of time keeping them optimal can be challenging. If you go to far with it you'll get possible precipitation or calcifying everything with a surface which is undesirable. Since doing that over time I just simplify myself some by reduction on the Ca needs of my reef tank, also I keep my ca targets lower than most. I know less corals aren't the prettiest thing in the world but they seem to do better. One other thing test kits made for the hobby isn't that reliable or consistent, unless your doing lab grade test daily you can actually swing your levels farther than you might think, never shoot for a dead on number, IMO.

Sorry sliding the topic off here, the internal & external pumps IMO both have pros & cons to each, I use or have used either & feel making work what fits your tank & situation best you can't go wrong. I do agree the submersibles will need cleaning more frequently because of reliability issues if you loose power you want it to start up after you gain power again.

[Ratpack]

Wow, thanks for all the insight. I have pretty much decided on external for the ease of maintenance, but the fact of vibrations cracking the glass has me a little worried. My sump will be an All Glass 30 gallon tank. On my last sump, Iused a piece of flexible tubing to connect the pump to the bulkhead, perhaps that would be a good idea here. I think the flex tubing would absorb some of the vibrations and not have a rigid pipe vibrating the bulkhead. What do you guys think? I certainly do not need a flood.

[golfish]

Originally Posted by scooterman

I don't think I would ever need to clean out a pump weekly though even if your running a kalk & ca reactor.

Have you ever use both?

[DonW]

Originally Posted by golfish

Have you ever use both?

Using both should not be an issue as long as they are set-up properly. When you see excess precip in your pumps it telling you that your not getting the full effect of the dosing and need to look at the method.

Don

[golfish]

Originally Posted by DonW

Using both should not be an issue as long as they are set-up properly. When you see excess precip in your pumps it telling you that your not getting the full effect of the dosing and need to look at the method.

Don