Water Flow: How is your water flow effecting nutrient export?

[revhtree Verified Admin]

Nutrient Export = Getting the nasties out of your tank so that you don't get nasty algae.

So bear with me here with this Question of the Day but I really would like some feedback on this! We're taught, for the most part, that a lot of flow is a good thing in a reef aquarium. I don't disagree and in most aquariums this is probably true. We really think through the positioning of our power heads and water movers based on the coral we are keeping and that's a good thing. But seldom do I read a discussion about the position of your water movers based on what's best for exporting nutrient and if and how that even applies. If I have missed it forgive me. I've seen very few.

If you have no substrate (bare bottom) then this is probably a mute topic today but your feedback and experience is very welcome!

Yesterday I was feeding my fish and performing a little maintenance I started thinking about the tremendous amount of flow that I had from my power heads that were all placed in the mid to upper region of my aquarium. Most people probably have their power heads positioned similarly because it keeps the sand from being less displaced and from causing sand storms in the tank. This got me thinking about ways I can better position them to help keep waste off the bottom and out of "dead zones" if you will and how to accomplish that.

Also what about your overflows? They are at the top of the aquariums and what is that tremendous amount of flow, in the upper water column, NOT allowing the overflows to skim some of the bad stuff? Or does that even matter? Does "too much" water flow keep some of the nasties suspended in the water column and out of the areas (sump, skimmer, filter socks) where it could be exported? That might be my dumbest question.

Let's talk about it today!


1. Do you think that the positioning of your power heads and water movers play an important part in nutrient export?

2. How have you used water flow to aid in the exporting of nutrients? Tips and tricks?

reef tank image via @rossco

 

[Lasse]

How would water flow contribute to nutrient export - can´s understand how this should work? A good flow from the return pump can help to transport organic matter down to the sump - but when it is there - other equipmens are needed in order to get organic matter out from the tank. Nutrients that´s dissolved (as PO4 and NO3) will not be removed by high flow.

If you want to transport organic matters and particles from your DT and have your sand bed there is should be - you must create a wave pattern that transport particles and mix the water totally

Sincerely Lasse

 

[Greybeard]

You've hit on one of the reasons why I decided to go to a bare bottom tank, with sox, changed every other day. Get the gunk OUT of the tank BEFORE it breaks down.

My pair of Tunze 6105's BLAST the bottom of my bare bottom tank, full force, 4x a day for 3 minutes. (vary from 15-25% the rest of the day) There's a little pile of heavier detritus that builds up in the lee of a rock island, where it's easy to siphon out once a week, with my normal water change.

My sump, since there is no macro refugeum, no light, is virtually pristine, after 7 months. Spiroid worms, a little bio film... that's about the only thing growing in there.

Couple high flow, excellent mechanical filtration, with the Zeovit system, and this is the first tank I've ever had where nitrates are not a problem. As my corals grow, I expect to need to dose nitrate in this system, but at the moment, I'm looking at 2ppm, with my fairly heavy feeding schedule.

 

[WVNed]

My nitrates are 5 with 35 fish including 2 eels and a lion. The trick with flow is to have it everywhere. Even in the sump. You keep everything suspended until it goes in a sock or the skimmer.

 

[Lasse]

I have not a super high flow in my tank - but I have no dead spots that accumulate organics - and if there was dead spots - my CUC will handle it. However - I have a wave pattern that mix my water in a vertical way, keeping small particles and bacteria floating and possible for my corals to catch. My corals have grow very much - if I should have the same effective flow with constant going streamers - it need to be more streamers than corals

Sincerely Lasse

 

[Paul B]

I think a high flow is very important to a healthy tank, but I don't think nutrient export has anything to do with it.

My tank also has very high flow but I don't have a sump so that wouldn't have anything to do with nutrients.
I also believe a natural tank, set up correctly, that is old enough doesn't need nutrient removal as it is a fully functioning eco system just like that crystal water filled ball you can buy with the live shrimp in it.

I rarely change water or add any supplements except calcium and alk. No carbon, bottled bacteria, Selcon, vitamins, Rowaphos (whatever that is) or anything else and my tank is very old.

Algae and sponges are a huge help and a bare bottom would be a detriment only because very little beneficial bacteria or pods live on plain glass.

 

[bigjgmac]

Well, not sure how much I have to contribute (some would say I should keep my mouth shut). I'm back in the hobby after a 20 year hiatus. The first go-round, I had a SW fish-only tank. Man oh man have things ever changed since the late 90s.

I currently have a 38 gallon bowfront with small sump, that is right at six months old. I use the sump for gas exchange and I run a canister filter for chemical media (carbon & GFO). I utilize two EcoTech VorTech MP10W propeller pumps for circulation. I currently have 6 fish yellow tail damsel, striped damsel (these two were the proverbial canaries in the coal mine when I started adding livestock), a six line wrasse, a kole tang, a clown, and a lawn mower blenny. Oh yeah, one cleaner shrimp. I have a variety of softies (half a dozen different zoas, purble ribbon gorgonian, nephthea, a couple of ricordea FL, two rhodactis mushrooms, and a crown leather). Also, there are a dozen small hermit crabs and five trochus snails.

Things seem to be going well and the although the learning curve was quite steep. I do a 10% water change weekly and 25% once every couple of months. I shut off the sump pump and canister, use the VorTechs to stir up the water column and turkey-bast my rock work prior to the water change while the sump & canister are offline. I try to suspend as much as I can in the water column and get as much as I can out when siponing the tank, figureing that a 10% change still leaves 90% of what was in the tank, still in the tank.

As mentioned, things seem good and so far all has been stable. I say that realizing it is still early days. I test weekly (salinity, pH, nitrate, phosphate, Ca, ALK, and phosphate). I'd like to get more debris out of the tank and I'm pretty sure that filter socks would be the way to go. When I jumped back in to the hobby, it was with a late 90s mindset and I had some dated ideas. I think an updated sump with filter socks may be a good way to go, but the space underneath my tank is pretty limited.

I welcome any thoughts should you choose to provide them.

 

[Lasse]

I think a high flow is very important to a healthy tank, but I don't think nutrient export has anything to do with it.

If you say water movement - I´m in. IMO - the movements real function is to move away excess oxygen from the micro habitats around the corals during photosynthesis

Sincerely Lasse

 

[damselindistress]

I have a bare bottom tank and have only one dead spot where detritus accumulates. This is where a lot of my snails hang out, with a few spaghetti and bristle worms. I siphon 2/3 of it out when I do a water change but always leave a little there for them to sift through as a supplementary food source for them. The tomini tang likes to snort around in it too - eww.

Sometimes I use a koralia pump on the bottom to make sure and blow out from under my rock, etc. It all goes into filter floss or is skimmed out. I do feel it helps keep my tank cleaner but maybe its just a mental thing - like a freshly vacuumed carpet.

 

[flabryth]

As I see it the flow is about both what's in the tank and getting stuff out of the tank and into the filtration system. If you have good flow...this means variation as well as the right amount circulation then your problems will now be about other the more nuance things like your chemistry and par. These two things both depend on flow to be more or less a constant because nutrient export and water circulation affects everything in your system.

Long story short get your flow right first before anything else.

 

[Belgian Anthias]

Nutrient Export = Getting the nasties out of your tank so that you don't get nasty algae.

And what would be the "nasties"?
Will I be able to influence algae growth in a way I may favor beneficial algae and suppress so-called "nasty" algae?
The water exchange rate there where the action is, of course, will be very determent for what may happen and influence activity rates.
if it is about daily turn over rates and filtration rates then we may talk about active nutrient management and the use of refugia and other biofilters. In that case, flow rates and the water content are determent for managing the nutrient content which makes controlling and managing nutrient levels an easy task

 

[ReefGeezer]

1. Do you think that the positioning of your power heads and water movers play an important part in nutrient export?
Some might argue that keeping organic particulate matter suspended is important. I would agree that flow that moves detritus to a filter or an easy place to remove it might help the tank look better and suspending POC might indirectly feed some types of coral, sponges, and etc.. I don't think it really helps lower nutrients though.

 

[Hydrored]

I run 2 MP40 at the bottom of the tank to push/keep all the nasties in the water column.

 

[jsker]

Lately I have been putting the thawed frozen food in the flow of my gyre to disperses the food throughout the system without feeding as much. My nutrients have good down, and that is by feeding less

 

[Back where it all began]

I use the eflux power head system. I dont have it set on a wave motion, but all of the power heads are set to produce a different volume of water pumped. This keeps things suspended and sometimes the power head will act as a blender and reduce particle size so hopefully corals, crabs, etc will get something to eat, the leftovers end up in a sock or the skimmer.

 

[guysmiley]

return flow is key a lot of people think the faster the system circulates the better but in order for your skimmer to remove organics efficiently it must have time to do so, if flows too much for it to consume it ends back in your display, i got tired of filter socks recently so made a pipe with multiple holes to act as a trickle feed that trickles over 3 different black sponge sheets the top sheet is Corse the middle sheet is fine and bottom sheet Corse my skimmer is well over rated for my system so it really draws crap out of the water column, i also run a refugium 24/7 that takes water from along side the skimmer the pump for that is behind the intake of skimmer , my refugium is full of copepods, on the bottom of my refugium is a 2 inch very Corse sponge over a foot long and the width of the sump, i weighed it down with a nice big bit of live rock, i got the idea from the advertised pod hotel ! long story short its crawling with pods bristle worms and heaps of other tiny life forms there is also chaeto growing in there i prune it right back to nearly the bottom once its formed a matt on the surface , its not the flashiest sump system but it didn't cost much to do a bit of diy but seems to be doing a nice job so far the sponge in return is super easy to clean compared to socks =) I'm always working towards new ideas to improve things and seems you can never know everything in this hobby lol now to get this khd puppy up and running and hopefully not too far off the ion d , covids put a bit of a wait on the probes as parts are needed from china =/ hopefully we don't have to wait forever .. anyway there's my last 5 cents =)

 

[Treefer32]

This is a huge question for me as well. I bit the bullet and added two mobius functional MP40s to my 340 gallon mixed reef for this very reason. I have patch works of hair algae growing throughout my tank. The worst algae growth is on the right side where I had 1 less powerhead. No flow from back to front (3 feet wide tank). The left side had one MP40 blowing back to front. Then I have 1 Skimz S18 (5000 GPH) towards the top on opposite sides of the 6 foot long tank. The left side had some algae. The right side all the rocks were clearly covered in some fresh green algae and some dieing (Gray brown hair algae). I added two MP40s to my display or an additional 6,000 to 8000 gph of flow during the die and around 2000-4000 gph at night.

The algae is still there, but all of the green hair algae is now dieing. I don't see anything solid bright green anymore. It's all brown and nasty. My skimmer seems to be pulling out more gunk. The foam consistency in the skimmer changed within 4 hours of adding the two new MP40s. The fish, I don't know what got into them but, I had to feed them twice what I normally feed because they ate everything I normally feed and didn't leave a single crumb. I don't know if it's increased oxygenation, decreased stale water, or what got into the fish, but they were way more energetic yesterday than I've ever seen them. Two days after adding the two new powerheads.

Maybe it's just something in the water, I don't know.

My LPS were all growing fairly slowly. The SPS are growing good. So, I'm hoping the increased flow, without blasting the corals helps with nutrient export, getting freshly oxygenated water to both the fish and the corals, and just overall decreases my green hair algae production in the display. My ATS went nuts this week. Nearly growing out of the scrubber a day earlier than normal (in 6 days instead of 7). I had to clean it or both the primary and backup drain would have been clogged.

My phosphates test out at .04 (red sea pro) and Nitrates test out at 12-16 (Red Sea Pro as well). PH cycles from 8.1 to 8.3 and salinity is around 1.025 and temp swings from 77 to 79.5 now with it being warmer outside. Alk tests out at 8.4 (Hanna checker) and Calcium tests at 440. Last I checked Mg it was over 1500 (close to 1600).

Salt I use is Instant Ocean. And I do every other week 11% water changes. Around 35 gallons every other week.

I really think doubling my circulation in the display is going to help, especially for this size tank. I probably should still have double this or two or three more MP40s. But, if this hobby wasn't so dang expensive!

 

[Shaun Sweeney]

I think moving water from the lower parts of the tank is important so I have a decent sized power head on the bottom facing straight up. I have another 1/2 way up on the back that also points up.

 

[Dhiren]

Id say its important but too powerful is not necessary...

Put some large dead mysis shrimp in and watch the bottom if any are able to settle on the bottom then u need more flow it should cycle slow enough for the fish to catch.

Reason being when the fishes **** it will eventually end up in your filters faster then break down instead of breaking down in your tank also this way your fishes won't be exposed to rotting food so hopefully no bacteria infection issues.

My water hardly goes bad i use tap water 24hrs old.
25% water change every 2 3 months
Been doing this for 20 years or so

I have all 15 yr old plus fish
1 emporor angelfish
1 blue ring angelfish
1 majestic angelfish
1 15 year old cleaner wrasse
1 yelow tail Corris wrasse
1 dragon wrasse

No clean up crew because they get eaten

 

[Dhiren]

Id say its important but too powerful is not necessary...

Put some large dead mysis shrimp in and watch the bottom if any are able to settle on the bottom then u need more flow it should cycle slow enough for the fish to catch.

Reason being when the fishes **** it will eventually end up in your filters faster then break down instead of breaking down in your tank also this way your fishes won't be exposed to rotting food so hopefully no bacteria infection issues.

My water hardly goes bad i use tap water 24hrs old.
25% water change every 2 3 months
Been doing this for 20 years or so

I have all 15 yr old plus fish
1 emporor angelfish
1 blue ring angelfish
1 majestic angelfish
1 15 year old cleaner wrasse
1 yelow tail Corris wrasse
1 dragon wrasse

No clean up crew because they get eaten

And another important thing is have the surface of the water moving powerful but have a place the bubbles can escape very important in natural nitrate removal the gasses need to escape.