Question on sump in basement.

[shermanator]

I'm planning on upgrading my 55 gal (HOB setup) to a much larger tank (280-300 gal) in two stages. First stage is adding a sump (maybe life reef custom) that will be in the basement (in a closet I'm building). I'm going to use a life reef overflow for my 55 gal. The large future tank will be drilled.

Two immediate questions:

1) Is it OK to use flexible PVC (spa flex) as the drain and return lines? There is about a 14' drop between the floors.

2) How do I go about figuring out what return pump to use?

I'm sure I will have more questions later. Thank you!

 

[MrClam]

The return pump needs to take into account a few factors. Essentially add all these factors up and that is the total GPH return pump you need.

1. Head loss
- You say the height difference is 14'. You also needs to account for head loss due to plumbing set up (i.e number of 90 and 45 degree bends, total pipe length, smallest pipe diameter) There is a calculator on the main RC page I believe

2. What do you want the return pump to do?
- If you are just using it to return water to the DT, then ignore this. If you are planning on running reactors or T-ing off the return line to a frag tank or a refuge then you have to account for this flow as well.

3. Desired sump turnover
- Whatever flow is left after running reactors and accounting for head loss will give your actual turnover rate.
- You need adequate turnover to at least match skimmer intake if you have one. There is some variation on recommendation for sump turnover depending on what you are trying to do, but roughly 5x DT volume through the sump is a good starting point.
- You also need to match the HOB overflow to this number, not the total return pump GPH.

HTH.

 

[shermanator]

Thanks, MrClam! For some reason, I missed the handy calculator.

I wanted to do the sump upgrade this summer and the big tank next summer. But I'm guessing (from your post) that using one skimmer / return pump setup for my current 55 gal and eventual 280 gal won't work.

Is there a consensus on what would be too high a flow rate through the sump, relative to DT? I would likely need 10-15x DT to make a skimmer big enough for a 280 happy. The lifereef overflows can handle that flow, but that might be crazy flow for a 55 gal.

Hmm, maybe I need to do this all at once? In that case, I'll have to stick with my HOB setup for a while. I don't mind changing the pump with the big tank, but needing a different skimmer (all I have is an HOB one now) would make it not worthwhile.

 

[JCurry]

I have a basement fish room with a remote sump, I use 3x1.5" spa flex drain lines and a 1" return line. My run in total is about 25' long and 12-14' in overall height. I'm currently using a reef flo 2700(?) blowhole pump and it is working every well. It also supplies flow to my reactors and frag system. On my old system which was very similar I used a reef flo barracuda pump which used a lot more energy.

 

[uncleof6]

Thanks, MrClam! For some reason, I missed the handy calculator.

I wanted to do the sump upgrade this summer and the big tank next summer. But I'm guessing (from your post) that using one skimmer / return pump setup for my current 55 gal and eventual 280 gal won't work.

No, it won't work for both. The 280 will require a far larger and more efficient skimmer, and a larger pump.

Is there a consensus on what would be too high a flow rate through the sump, relative to DT? I would likely need 10-15x DT to make a skimmer big enough for a 280 happy. The lifereef overflows can handle that flow, but that might be crazy flow for a 55 gal.

There will never be a consensus on this, and the avialable information concerning it is outdated by 30 years or so. Also, the skimmer flow rate, has nothing to do with flow through the sump. This "link" is an example of distorted information, with no data behind it. I draw the line at 10x the system volume (different from tank volume.) There is no reason not to go higher, but I can do a dissertation on why to not go lower, well...present a thesis defense anyway, the dissertation would be infinitatley more complex.

Hmm, maybe I need to do this all at once? In that case, I'll have to stick with my HOB setup for a while. I don't mind changing the pump with the big tank, but needing a different skimmer (all I have is an HOB one now) would make it not worthwhile.

LifeReef, nor anyone else, manufactures an HOB overflow that will actually handle 2800 gph. Tanks in the larger sizes require more functional designs, more attention to detail, and a different mindset than little hobby tanks.

The handy calculator on the front page, goes at the problem from the wrong direction. Calculating a pump fed system starts with setting the flow rate as a constant, and then using friction loss charts, determining the pump requirements, and then applying the results to the flow curves of various pumps to find the best match, which will usually be + a few hundred gallons more, which is fine to accomodate reactors and auxilliary equipment.

 

[shermanator]

No, it won't work for both. The 280 will require a far larger and more efficient skimmer, and a larger pump.

Thanks for confirming. Originally I hoped to use the larger skimmer and pump with the 55 for now, but my new plan is to do the sump and plumbing upgrade this summer and use my HOB skimmer (Remora Pro) in the sump until I get the bigger tank next year when I'll also upgrade the skimmer and return pump.

Lifereef, nor anyone else, manufactures an HOB overflow that will actually handle 2800 gph. Tanks in the larger sizes require more functional designs, more attention to detail, and a different mindset than little hobby tanks.

Sorry for the confusion I meant 10x my current 55 gal. For the 280, I plan on having that drilled. Because my 55 gal isn't drilled and filled with life, it's easier to use the HOB overflow for now.

The handy calculator on the front page, goes at the problem from the wrong direction. Calculating a pump fed system starts with setting the flow rate as a constant, and then using friction loss charts, determining the pump requirements, and then applying the results to the flow curves of various pumps to find the best match, which will usually be + a few hundred gallons more, which is fine to accomodate reactors and auxilliary equipment.

I'm going to worry about the 280 next year and will change pumps and get a new skimmer at that time.

Just to ballpark for a 55 gal, it's looking like a Mag12 will work out okay (without reactors, etc) based on the calculator's approximation.

 

[uncleof6]

It will work if you use 1.5" return plumbing. It is a very poorly engineered pump, and I highly do not recommend their use, till the engineering issues are fixed, and they won't be fixed, been the same for 30 something years....

 

[ca1ore]

I draw the line at 10x the system volume (different from tank volume.) There is no reason not to go higher, but I can do a dissertation on why to not go lower, well...present a thesis defense anyway, the dissertation would be infinitatley more complex.

I'd be curious to hear your reasoning for not wanting to go less than 10x system turnover. I'm open minded (I think?), but cannot frankly see any good reason to go higher then 3-5 times (I actually do more like 2-3 total system turnover). Adequate surface skimming, uniform temperature ..... what else?

 

[uncleof6]

I'd be curious to hear your reasoning for not wanting to go less than 10x system turnover. I'm open minded (I think?), but cannot frankly see any good reason to go higher then 3-5 times (I actually do more like 2-3 total system turnover). Adequate surface skimming, uniform temperature ..... what else?

It is not easy to defend arbitrary numbers. All the flow rate numbers quoted for the past 40 years, are simply arbitrary numbers, "as you need a lot more flow," does not help much....

Does the increase of recirculative flow rate, in a closed system marine aquarium, have a positive affect on the overall conditions within the system?

This is the question that invariably gets asked, when this topic comes up. The answer to that question is very complex. though there is an unequivocal answer, and the challanges to that answer ambiguous at best, given in small doses that are digestable in a forum venue, often suggests a deliberate intent to mislead by avoiding clarity.

By examining dissolved organic levels, dissolved oxygen levels, and biological oxygen demand, It can be seen that by increasing the flow rate, dissolved organic levels decrease, biological oxygen demand decreases, and dissolved oxygen levels rise. this is important, as it offers the hobbyist a glimpse into the actual functioning of their system.

OR:

Although hobbyists might assume that the rules of thumb decided upon 40 years ago apply to systems as they are run today, and that powerheads can be used in an additive role in recirculative flow rate, it is my argument that these rules of thumb are adhered to based on power consumption, rather than facilitating the processes that must occur in the closed system marine aquarium.

Neither would pass a thesis committee: they are still half baked...

Just one little piece of the puzzle:

If we accept the assumption that the rate of TOC (total organic carbon) removal is proportional to the amount of TOC in solution, (Feldman, et al, 2008), then it makes sense that the higher the concentration of TOC in a skimmers influent, the higher the rate of removal will be.

Setting up our system, we use 2x - 3x system volume for our recirculative flow rate (becasue that is all the skimmer can flow.) Since this is nowhere near the "rule of thumb" flow rates for reef tanks, we add powerheads to achieve the 40x - 100x system volume needed. (That seldom if ever is achieved in practice.) Voila, it works. The skimmer foams, there is no surface film, but...are we really looking at this objectively?

Given: Dissolved organics accumulate at the water surface. Since the rate of flow out of the tank, is magnitudes lower than the vertical mixing of the tank, the organics are not accumulating at the water surface, rather are being mixed back down into the tank. There is no surface film, the skimmer foams, therefore the system "works great"... although there is some removal, (the skimmer foams,) the concentration of organics in the skimmer influent, is low, and the removal rate correspondingly low.

If we turn the table, by increasing the recirculative flow rate, and demphasize the "in tank flow," the surface accumulating organics get removed from the tank, rather than mixed back down, the concentration of organics in the skimmer influent increases, and the removal rate increases. The result is increased skimmer performance, a reduction in dissolved organic levels, and decrease in biological oxygen demand (breaking down organics requires oxygen) and an increased level of dissolved oxygen.

It is then logical to deduce that adhering to the "additive" point of view, actually contradicts/hinders the function of the dissolved organic removal process...this places addtional burden on everything else in the system, because precious recources (mainly oxygen) are required to process the organics that could be removed.

Still, just one part of the whole.

When the shift, (from closed systems to "open systems" in use today...) occured, dead spots in the tank became a problem. powerheads where added in the tank, to eliminate the dead spots. Somehow, overtime, this has been distorted into the bulk of the flow is powerheads, and recirculative flow is just there because. The powerheads were not added because coral need strong chaotic flow (yes flourishing reef tanks were a reality even back then) rather to rid the tank of dead spots. What the coral really need is "clean" oxygen rich, dissolved organic poor (unpolluted,) water in copious amounts...as well as food.

Most reefers, even novices, have the nitrogen cycle down pat. However, ammonia is not the real issue in marine aquaria. The main issue is dissolved organics, the critters excrete dissolved organics directly into the water, rather than ammonia as in fresh water. (No, ammonia is not an organic compound, unlike what I read recently in a rather literate argument for organic carbon dosing...)

I know of one reefer on this board, that did increase his recirculative flow rate significantly, and immediately noticed his corals opening up further. Why? You tell me...

From here we get into gas exchange, pH stability, and beyond to things such as weir (overflow) design, etc.

Offered for informational purposes sincerely, albeit a little tongue in cheek as there is nothing in this that I have not put forth before on this forum, in both small and large doses.

 

[MrClam]

DI think I would have to challenge your premise that dissolved organics accumulate at the surface. While this is a true statement, your argument is based on the assumption that this is a universal truth. These are honest questions, as I have no data.

My question is two fold.

1. Does it hold true that if you remove all of the surface proteins from the system all of the dissolved proteins will precipitate (for lack of a better word) to the surface until there are zero dissolved organics and only surface organics? If this isnt true, it would be important to know the threshold of dissolved organics necessary in order to get concentrated surface organics. It is quite possible that the typical state of most tanks could be below that threshold normally.

2. What is the rate of accumulation of the hydrophobics at the water surface? Your argument assumed that the in tank flow created by Powerheads effectively mixes the hydrophobic proteins into solution. Im not a chemist (maybe one could chime in) but i believe the rate of mixing necessary would be very high (based simply on trying to mix oil and water). In addition, the assumption is made that by slowing the flow it will aid in surface protein accumulation, but how low of a flow would be needed to achieve such a result? Most tanks have no surface proteins. If the flow would have to be as low as 5x total turnover to facilitate surface protein precipitation would that not have an overriding negative effect on gas exchange and nutrient transport?

If I butchered any of your logic I apologize. Its been a long day.

 

[uncleof6]

DI think I would have to challenge your premise that dissolved organics accumulate at the surface. While this is a true statement, your argument is based on the assumption that this is a universal truth. These are honest questions, as I have no data.

My question is two fold.

1. Does it hold true that if you remove all of the surface proteins from the system all of the dissolved proteins will precipitate (for lack of a better word) to the surface until there are zero dissolved organics and only surface organics? If this isnt true, it would be important to know the threshold of dissolved organics necessary in order to get concentrated surface organics. It is quite possible that the typical state of most tanks could be below that threshold normally.

Theoretically yes. Lacking a continuous input of organics, as they are removed from the surface, the surface would film again, until there were no more organics in the reservoir. In a perfect world anyway...

In a running system, I don't see that it is possible for the organic levels to be at a level that would not produce a surface film.

2. What is the rate of accumulation of the hydrophobics at the water surface? Your argument assumed that the in tank flow created by Powerheads effectively mixes the hydrophobic proteins into solution. Im not a chemist (maybe one could chime in) but i believe the rate of mixing necessary would be very high (based simply on trying to mix oil and water). In addition, the assumption is made that by slowing the flow it will aid in surface protein accumulation, but how low of a flow would be needed to achieve such a result? Most tanks have no surface proteins. If the flow would have to be as low as 5x total turnover to facilitate surface protein precipitation would that not have an overriding negative effect on gas exchange and nutrient transport?

If I butchered any of your logic I apologize. Its been a long day.

This would depend on the rate that organics are added to the system.

The flaw in your logic here, is the belief that most tanks have no surface proteins (organics) which is simply not true. Also, the "organics" do not actually "mix" into solution, as they are not water soluble. They are in suspension (a more appropriate term) in the water column, and can be held from accumulating at the surface, by strong mixing downward. as you noted when mixing oil and water, as soon as the mixing stops the oil hits the surface. You may also have noticed that in order to remove the oil, it has to be at the surface. If it is down in the water column (suspended) it cannot be removed. The compounds we are talking about, though "oily" (related to oil in some ways,) are not 30 weight oil.

What we want is to take a very thin top layer, which (whether you can see the slick or not) will be higher in organics. However, we want to take it off rapidly, (surface renewal) so these organics are not mixed back down.. if that makes sense to you. It is not a perfect process, however, we want to get as far ahead as possible. As I tried to indicate, this is far from a complete thesis, and needs further cooking. It is only carried far enough to present a challange to the notion that 'the flow rate only needs to match the skimmer needed flow rate, because that improves skimmer performance.' Simple logic would contradict this, unless the skimmer is fed water from the drain line, rather than taking from the sump and returning to the sump.

 

[RobinsonFam1]

I can tell you that witha 14 foot drop to sump it will create a siphon and change your drain and return rates. I say this from personal experience.

I had a 90 gal with hammerhead as return. About 3600 gph if I recall correctly.

I used the drains as a direct skimmer feed in form of a down draft skimmer and it worked perfect.

You will probably not be able able to transition from 55 to 280+ as a direct transefer. To many flow differences. Id suggest a big feed tank or tub or sorts as a sump to hold skimmer etc.....seperate setup for fuge, reactors, etc....seperate system for water changes etc....

Look at other threards for salt water mixing stations.......auto top off.......lots of ideas out there to help you get started

 

[ca1ore]

About the only study I recall reading on skimmer performance noted, if memory serves, that DOC removal was limited to about 30%. Whether a higher recirculating rate ups that to 35%, and a lower one to 25% (just an illustration) I know not. Just seems to me all the prior arguments put forth may have academic but not practical impact. I'd be interested to see whether increasing the recirculation rate on my tank would cause the 'corals to open up more' but that would necessitate a really monstrous pump - which isn't in the cards at the moment. My own anecdotal observations suggest recirculation rates don't have major impact, though to be fair, that's on different tanks at different stages of my reefing experience - thus of hardly any scientific value. Fascinating discussion though ....

 

[uncleof6]

About the only study I recall reading on skimmer performance noted, if memory serves, that DOC removal was limited to about 30%. Whether a higher recirculating rate ups that to 35%, and a lower one to 25% (just an illustration) I know not. Just seems to me all the prior arguments put forth may have academic but not practical impact. I'd be interested to see whether increasing the recirculation rate on my tank would cause the 'corals to open up more' but that would necessitate a really monstrous pump - which isn't in the cards at the moment. My own anecdotal observations suggest recirculation rates don't have major impact, though to be fair, that's on different tanks at different stages of my reefing experience - thus of hardly any scientific value. Fascinating discussion though ....

There is no evidence to suggest that a higher flow rate will up the percentages of TOC removal. There is also no evidence to suggest that lower flowrates affect the percentages of TOC removal. What is investigated is the rate of removal, e.g. how long does it take for the ~30% to be removed, vs the production or "pollution rate." E.G. the longer it takes to drop the TOC, the larger the demand on the resources of the system. We cannot get the TOC to zero, or anywhere near it. But that is not the point.

It is important to remember, that this is just a part of the whole and only scratching the surface of the subject of recirculative flow rate, its affect on gas exchange, pH stability etc. Consider that saturation of dissolved oxygen (depending on salinity, temperature) is ~ 6 ppm. At 3.5ppm the critters begin the death struggle. With such a small window, and considering they do not knock on the glass and yell at ya, any gain in dissolved oxygen levels has a significant impact.