Tall tank flow question

[smb2415]

Let me start by saying, Im still very much a newbie at this. My DT is 42" tall (7' long x 3' wide) and I believe I am experiencing some flow issues on the bottom. Perhaps I should have plumbed for closed loop, maybe I don't need any additional flow, or perhaps my idea of using additional MP40s will be suffice.

Im wondering what is the height of your tank and and if you use any closed loop or other flow for near bottom flow?


Background reason I bring this up is below. However I really don't want to make this about cyano or DSBs, theres plenty of reading for that. I more interested in figuring out proper flow for these tall tanks... I am thinking at least somewhat rationally that I need more flow on the bottom?

I am fighting cyan and Im not making much headway. My lights run about 10-12 hours daytime - ramping up and down, then have about 9 hours of reduced moon phase lighting, and the rest lights out.... if my memory is correct. Return pump is a rifle hammerhead, valved down so I have a controlled waterfall on the coast to coast. theres (4) 3/4" returns 2-middleish, 2 rear. Then theres an MP60s center mounted, on length of tank, about 1/3 down from top or about 8 - 16" down (varies between each end).I can see that theres "room" for increased flow down low. To combat the cyano last night I vacuumed a small section of the deep sand bed (a choice I made, for a few reasons) and removed quite a bit of detritus along with cyano. I believe this points back to needed more flow and feeding less (which Ive started curbing already).

 

[dave.m]

How old is this set-up? You have to allow that you will go through a succession of algae explosions in the first few months in many set-ups. What sort of subsurface clean-up crew do you have in the sand? I suggest nassarius snails and fighting/tiger conchs. You will never get rid of invasive algae if you're not cleaning up/exporting fertilizers..

Dave.M

 

[smb2415]

Hi Dave.M - The tank is 1 year old (post cycle). I have 3 conchs (2 tiger, 1 hawk), countless small snails, some margarita - nassarius - and Mexican turbos...not sure how many, not enough but more and 2 dozen. My valentine puffer has had quite a snack so I'll need to restock with probably another 12 turbos and 100 nassarius, also thinking of adding 2 cucumbers. I have to engineer gobies - although their area is well dug out and seemingly clean.

recommendations/suggestions?

 

[smb2415]

FWIW the cyano mostly retracts at night however during the daylight it really sprawls out.



An older photo but shows scaping of tank and height of MP60. Other MP60 is under the C2C overflow box.


To give a perspective on tank height

 

[dave.m]

A pair of diamond gobies can help with the sand sifting, but only to a point, as you have a very deep sandbed. What about bristle worms? They can also help keep the sand clean. And yes, get some more nassarius snails if you have a puffer. Make sure some actually reach the sandbed.

Dave.M

 

[smb2415]

bristle worms so far have been hard to come by. At least I haven't found any source other than ISPF and fellow reefers. If you know of another source please do share, not really looking forward to paying $100 for a ~dozen worms.

 

[dave.m]

Live rock would be a good place to start, preferably pre-quarantined.

Dave.M

 

[Jeff210]

I believe you definitely need additional flow in a tank that size. As a point of reference, on my 72x24x25 210 gal, I have a maxspect gyre mounted about 1/3 of the way down from the top on one end and 2 MP40's - one behind my rockwork and one in front of it - as close to the sand bed as I can place them without stirring up the sand = on the opposite end.

Since you are a Vortech guy, I would suggest a couple MP10's on the back to provide back to front flow and moving your 60's down to provide end-to-end flow around your rock...

 

[smb2415]

Jeff, funny you should mention that as I looked into getting MP10s for that purpose however they are only "supported" on up to 3/8" glass, I have 3/4". That means I have to step up to the MP40 which is bigger, more flow than needed, and more $.

I just purchased a used MP40 for exactly this purpose. Between you an Dave.M it seems my thinking isn't too far out of line. Vacuum current mess, replenish cleanup, add flow, and feed less.

~~ on the comical side, imagine trying to rig a makeshift contraption to siphon the sand bed while standing on the ladder..... lots of spilt water, 10' of tubing and 12' power cord... wish I took a picture before I gave up.

 

[jarvis]

Can you rig up a support for the MP 10s since they will be in the back of the tank? one that doesn't have to use the glass magnet. and save some coin on MP 40s our use them elsewhere in the tank for more flow as you already bought one. I would say more flow. I would stick with the DSB. I know I sure wouldn't want to siphon your tank if you switch to a shallow sand bed.

Closed loop lost it luster. its power hungry, but you do get the benefit on not having no visible power heads. power heads today push alot of water from small power now. I question what people were thinking drilling holes so low below the water line. still do. The high hole drill is cool just not for me.