Felicia's 30 Gallon Seahorse Tank - Seahorses have arrived!!!

Specs
Tank
30 Gallon Oceanic Glass Cube - 20"W x 18"D x 20"H

Lighting
Coralife Aqualight 20" 96W Quad Power Compact
(This came with the tank and is probably just temporary until I get an LED fixture.)

Current Plans
The plan for this tank is to have it house 2 female H. Erectus seahorses. I'm also planning to keep some seahorse compatible fish and invertebrates in here as well. I plan to have this tank be a colorful and lush mix of macroalgaes, soft corals, and gorgonians.

1) Cleaning the tank - the tank was sitting dry for quite some time and has hard water stains that have etched the glass. Luckily Brandie and Denzil just figured out how to solve this issue on Brandie's used 210! Brandie and Denzil offered to help me polish the glass with cerium oxide this weekend.

2) Painting the stand - I really don't like the two-tone wood on the stand, so I will be painting the entire stand black to match my bedroom furniture. I'm still deciding the best way to do that. I'm thinking a spray primer and then black satin spray paint. I also may end up painting the trim on the aquarium black with Krylon Fusion spray paint.

3) Tank design - I'm planning to partition off the back 4" of the tank with 1/4" black acrylic. This will have a surface skimming overflow and return nozzle and will hold the heater, filter media, a refugium area for pods, and a return pump.

 

I need some input on the design of the back chambers. Here's my sketch of what I think will work including the dimensions. The depth will be 4" between the back of the tank and the acrylic partition.


I plan to have the overflow be toothless, so it will just be a smooth rectangular cut-out. I'll add some black plastic gutter guard to keep fish out of the back chambers. I plan to use a Maxi-Jet 1100 return pump, which has a flow rate of 294 gph. I know the overflow needs to have a flow rate slightly higher than that, so I used the weir flow formula to calculate the width of the overflow for a flow rate of 300 gph. I need a 4.75" wide overflow with the water 0.5" above the bottom of the overflow cut-out.

The media rack will hold filter floss, Chemipure Elite, and Purigen. The refugium section will hold chaeto/ochtodes and serve as a protected breeding area for pods, which the seahorses will munch on.

Please give me any feedback on this design!

 

I really like it! I too am building and AIO out of a non AIO tank. I am interested on this overflow formula you have for GPH. That is the part I find myself stuck at. How many slots, how tall, how wide ect. I am tagging along for this one.

 

I decided not to use teeth/slots because a) it will cost a lot more money to have those cut in than just a rectangle and b) because you actually get more efficient surface skimming without slots. The only real plus to the slots I could find after a lot of googling and reading is that they keep critters out of the back chambers. To solve that I'm just going to silicone some black plastic gutter guard (couple bucks at home depot) over the rectangular overflow cut-out to prevent any animals from going over the overflow.

The formula I used it the standard formula for flow over a rectangular weir. It seems like it should apply just fine to this problem since I'm just going to use a smooth rectangular overflow. Here's the equation:
q = 2/3* cd * b * (2 g)^(1/2) * h^(3/2)
where
q = flow rate (m3/s)
h = head on the weir (m)
b = width of the weir (m)
g = 9.81 (m/s2) - gravity
cd = discharge constant for the weir - I used 0.62 which is an average value

You just have to convert from gph to m^3/s to use it. That's how I got what the width of my overflow should be. I hope that works! If anyone else has another way of figuring out the overflow width, let me know!

 

Well that makes me curious if size even really matters? Couldn't you just make any ole cut out and get good flow? Only downside would be if it was too small you would be pumping out the back chamber before the overflow can replenish it.

I am quite new to the DIY AIO and overflows for the matter. That seems like a lot of math just to figure out overflow rate. My pico came with a 54 GPH pump and I replaced it with a 183gph pump and there is no difference in water level in the back chamber.

Now I confused myself! Lol

 

Hmmm, I'm new to any kind of AIO system or plumbing a tank for that matter. My main tank just has an AC70 HOB filter and that's it. I read an article on understanding aquarium plumbing and it made the statement that you want your overflow rate to be just a bit higher than your return pump rate. They said if the overflow is too wide, you'll get lots of turbulence and bubbles and if its too narrow then you'll end up with water on the floor. I understand the too narrow issue because if your pump pumps water out of the chambers faster than water can flow back in, then you'll end up with more water in the display portion of the tank then there should be and it will overflow. It seems like erring on the side of too wide is better. I don't think it really makes that much of a difference as long as your pump doesn't go faster than the overflow.

 

Not sure if you already are planning to do this.

If you paint the back, make a cutout to attached a macroalgae "grow light/LED" on the back of the tank. That way you can grow macroalgae on reverse daylight and such and you will get 6"x18"(?) side lighting area vs 6"x4" top lighting.

And you won't have to worry about light bleed into your bedroom.

 

Great point! Thanks! I think if I put in the acrylic partition, I won't end up painting the back since you won't see it anyway. But I hadn't thought about attaching the light to the back to get more lighting area. I was just thinking of above. Thanks for pointing that out. I'll have to find a little LED light to use for the fuge section that I can somehow mount to the tank back.

 

You will want to paint the back anyways. That way you can create "cryptic" fuge areas for animals that prefer dark areas. Also helps inhibit micro algae growth in your media basket from the macro grow light (or from reflected/scattered tank lighting or your room lights.

 

Good to know! I had no idea. I've got a can of black krylon fusion on hand so that will be easy to do. Do I need to paint the 4 inches on the sides as well? Or will just the back be enough?

 

Up to you.

For symmetry, and depending on if you use black acrylic "dividers" between the sections... Light may leak through to other sections.

 

I do plan to use black acrylic dividers, so light would only get into the two outer chambers if I don't paint the 4" on the sides. That means light would get to the heater chamber and the return pump chamber. It seems like that shouldn't be an issue, so its probably just an aesthetic decision.

 

Outer chambers sides unpainted would let you see the heater (and if it had a temp display).

Return pump would let you see what is going on. AND you could put/build a skimmer in the last chamber. Either air pump driven or use another Venturi pump.

 

Actually, your middle two chambers are better as skimmer chambers because of constant water levels.

Your last chamber will be used as your "flex water" for auto-topoff purposes.

 

Yeah, I think I will want to be able to see the return pump and the heater so I'll leave the sides unpainted. I do want to put an ATO on this tank, so its good to know that the float switch should be in the 3rd chamber with the return pump. I'm trying to avoid a skimmer because I just really don't like them, but if I find I need one (seahorses need really stable water quality), then I may put a nano skimmer in one of the chambers. So it would need to be in the fuge area for constant water level? I wonder if it would be ok in there with the pods and macros.

 

It's my understanding that you want unskimmed water to enter the fuge first to feed the fuge the nutrients it needs then skim then return pump. I thought I had read that somewhere.

 

Slimmer in your media chamber could work, but will introduce micro bubbles into your refugium. Then again, skimmer in refugium would introduce bubbles too.

 

Check out my BAR tank journal where I have images of my sump "water flow". But I doubt you have the space to do all of that.

Actually, look at the aquapod 12g back chamber layout for inspiration. They have a "bottom half section" cryptic refugium section. (part of the return pump part).

 

Hmmm, all so complicated. I think at this point it would all be an issue of space. There's no way a skimmer would fit in the section I designed for media. It would however fit with the heater in the first chamber, but would that have an issue with changing water level? I could add it another middle section after the fuge that would have constant water height, but that would take away over half the space from the fuge. This is why I'm trying to avoid a skimmer, haha.

 

So this could be an option with a skimmer. Would this work?