How do I know if I have the right amount of flow?

[EntitledSushi]

I have a 75 gallon Red Sea Reefer 350 XL. My corals have not been doing well. I have some basic "beginner" corals, like Zoanthids and some LPS. My tank has had some struggles lately, including that my Gyre Pump broke and it took me a week to get a replacement. Bu I took the opportunity to read up a bit on flow and the impression I got was basically more flow is better. So I set my Maxspect XF230 Gyre Pump to 70%, vs 40% before. Clearly the flow is a lot greater. But, the LPS corals are more retracted and generally looking unhappy. Is it likely the flow is too high? Or maybe the unhappy LPS's is just a coincidence? Is there something I can measure to check that I have the appropriate amount of flow?

 

[GaryE]

I have a Gyre pump. Set on 10% everything in my tank gets very unhappy. I have had it turned off for the last week and everything seems happy.

 

[mike550]

I have a 75 gallon Red Sea Reefer 350 XL. My corals have not been doing well. I have some basic "beginner" corals, like Zoanthids and some LPS. My tank has had some struggles lately, including that my Gyre Pump broke and it took me a week to get a replacement. Bu I took the opportunity to read up a bit on flow and the impression I got was basically more flow is better. So I set my Maxspect XF230 Gyre Pump to 70%, vs 40% before. Clearly the flow is a lot greater. But, the LPS corals are more retracted and generally looking unhappy. Is it likely the flow is too high? Or maybe the unhappy LPS's is just a coincidence? Is there something I can measure to check that I have the appropriate amount of flow?

@EntitledSushi welcome to the world of words that can’t be defined. As a newbie myself, “medium” flow or “strong” light drive me nuts. I have very limited experience but here are my few thoughts. But I‘m sure others with more experience will provide better advice.

First, how were your corals doing before your gyre broke? It could be that your water parameters aren’t right for the corals.

Second, if your corals we’re doing well before your gyre broke then it could be flow. But the amount of flow a coral likes or needs varies on the type of coral. So “more is better” doesn’t always work out.

Finally, lighting can also be a factor on your success wirh corals. Some corals need more than others. Some are more tolerant of the level of light. But at least with light you can measure intensity using a PAR meter.

Sorry that this is a bit of a non-answer. Good luck!

 

[muzikalmatt]

Flow is one of the hardest things to get right and even harder to "know" when you've gotten it right, especially in a mixed reef as the flow demands vary so much between the corals. One thing I've found is much like any other adjustments you make in a reef tank, you have to wait a while for the effects to manifest. The corals may look unhappy at first after a flow change, but given time to adapt they may ultimately be happier and healthier. Overall though, once I got my flow where I felt it was good enough throughout the tank I've tried not to mess with it. Stability is key, and that includes flow. Now I favor moving corals to spots that have better flow for that specific coral rather than adjusting the flow for the entire tank.

 

[WVNed]

I have 2 XF350 pumps in my 75 running in alternating gyre mode at 60%. I doubt you have too much flow. There are xenia, zoas and mushrooms in with gorgonians that have enough flow to be happy.


I would turn the pump back down to 40% though and slowly ramp it up. I am only running my lights at 50% over my softie tank.

 

[EntitledSushi]

@mike550 unfortunately I can’t give a black or white answer about whether the corals were better with the old gyre, new gyre, or no gyre. Other stuff was going on, like the one of my two lights broke and it took two weeks to replace it. In the interim a number of things suffered. I also moved stuff around because of the lights. I do wish somebody could say “x” flow rate is good, since that is something I could act on. Maybe that’s wishful thinking though.

 

[mike550]

@mike550 unfortunately I can’t give a black or white answer about whether the corals were better with the old gyre, new gyre, or no gyre. Other stuff was going on, like the one of my two lights broke and it took two weeks to replace it. In the interim a number of things suffered. I also moved stuff around because of the lights. I do wish somebody could say “x” flow rate is good, since that is something I could act on. Maybe that’s wishful thinking though.

Wow. You have a lot going on. Work on getting the lights and gyre running and stable. What are your water parameter?

 

[EntitledSushi]

@WVNed why do you have two pumps? Are they on opposite sides of the tank? I could see how alternating flow might have a different effect than just one direction.

 

[SoAg Reefer]

I run almost 100x flow rate for a mix reef, sps dominate. You can always avoid high flow for lps by mounting them where rocks block any direct flow or in parts of the tank with less flow. There are flow rate guides if you google search and it’s simple math to get to where you need to be. Hardest part is avoiding direct flow but that’s a mounting thing

 

[Gernader]

@EntitledSushi I have a 75g that is 4 feet long and I’m using hydor koralias in total of 3,400 gph of flow. I have 2 nanos mounted in the back and a powerful one at the side of the tank. It’s enough to keep all types of corals happy.

 

[EntitledSushi]

Wow. You have a lot going on. Work on getting the lights and gyre running and stable. What are your water parameter?

pH = 8.1
Ammonia = 0 ppm
Nitrite = 0 ppm
Nitrate = 12 ppm
Salinity = 1.026
Phosphate = 2.0 ppm
Calcium = 440 ppm
dkH = 10
Temperature = 77.8 degrees

I’ve been using NO3-PO4-X to try to reduce the nitrate and phosphate, with modest effect.

 

[EntitledSushi]

I run almost 100x flow rate for a mix reef, sps dominate. You can always avoid high flow for lps by mounting them where rocks block any direct flow or in parts of the tank with less flow. There are flow rate guides if you google search and it’s simple math to get to where you need to be. Hardest part is avoiding direct flow but that’s a mounting thing

What does 100x flow mean?

 

[WVNed]

2 gyres opposing each other gives you a back and forth random flow.

 

[mike550]

pH = 8.1
Ammonia = 0 ppm
Nitrite = 0 ppm
Nitrate = 12 ppm
Salinity = 1.026
Phosphate = 2.0 ppm
Calcium = 440 ppm
dkH = 10
Temperature = 77.8 degrees

I’ve been using NO3-PO4-X to try to reduce the nitrate and phosphate, with modest effect.

So phosphates seem high to me. If you have GFO that can bring down the phosphate pretty quickly. I just put GFO in a media bag and put it in my sump where there is flow. Nitrates and Alk might be a shade high but I don’t think that’s the issue.

 

[Chefwheredyougo]

Off the top of my head I can't think of any coral that likes to get direct flow. Euphyllia and brains generally like a low-moderate amount of indirect flow that will bring food to them and remove waste, but not enough to tear the flesh. I have a 3k gyre that's used for mixing water only now. It's harder to dial in gyres imo. Attempts at setting it low enough to not blow my sand around, but high enough to actually function as a gyre in my 75 were fruitless. I gave up after a few months and went with 2 tunze on opposite sides.

Not saying the gyres don't work, but imo powerheads are better. Easier to direct, longer time between cleaning, and better flow options with powerheads.

Also, be careful with nopox. You'll bottom out quickly and then worse problems arise.

100x means 100 times turnover of tank volume.

 

[SoAg Reefer]

GPH.....your water volume x gph of all pumps including the return at the levels you run the, not the max unless u run max all the time = turnover. So if you have 50 gallons total a 100x turnover rate is gph of 5000

 

[EntitledSushi]

A lot of helpful information here, thanks! At this point I'm thinking total flow is not too far off (I calculate 50x flow), but maybe I shocked the corals especially going from no flow for a week to that rate. I'll dial it back to about 30x and try to make sure the corals are somewhat protected from direct flow.

 

[Dragon52]

@WVNed why do you have two pumps? Are they on opposite sides of the tank? I could see how alternating flow might have a different effect than just one direction.

I have 2 MP40s set on reefcrest mode running between 20-80% of flow os it's up & down & I'm finding I can keep some corals I wasn't able to when using other pumps that didn't allow me to fluctuate the flow.