Newbie Question - HOB size for 75 gal

[Janelle]

Would love to get your opinion on size of HOB to use for a 75 gal planted tank.  I’m leaning towards angels and some other small schooling fish to fill in.  
 

Would you use 2 55’s or a 110?  (Or maybe a 75 is enough??) I am planning on adding a sponge filter or 2 as well.  Or maybe I don’t need the sponge filter??  But I like the idea of having one in-case I need to set up a hospital tank I will have something ready to go. 

Also, where do you like to place the filter??  At one end or in the middle of the tank?

Thanks so much! 

Edited January 17, 2021 by Janelle

[gardenman]

The size of a HOB is more dictated by the fish than the size of the tank. In a planted 55 with a small fish load, the sponge filters alone would be adequate. Angel fish and small schooling fish aren't especially messy. (Compared to large cichlids like Oscars or the like.) Angel fish tend to prefer quieter water also, so I'd go smaller on the HOB and use sponge filters. As to placement, in theory if you place the water flow outlet near a sidewall, the water coming out along that wall will help to create a somewhat circular flow of water in the tank with the circular flow ending at the intake where all of the debris will get sucked in. That theory tends to die as soon as the water hits the first corner, but that's the theory anyway. With most filters expelling water on the right then most HOBs should be put on the back far right corner so they create a flow to the right front corner, that will then move across the front of the tank to the left front corner, then back to the back left corner then across the back to the water inlet on the filter. The ninety degree corners, plants, decorations, etc. all tend the destroy that theory as they disrupt the flow,  but that's the theory behind HOB placement. In the real world, it doesn't really matter where you put it.

[Janelle]

Thank you for the feedback @gardenman

Would love to get more input from others as well!  TIA

[quikv6]

Hey Janelle,

I have a 110 Aquaclear on a 75 gallon Molly/Platy tank with lots of fish, mostly juveniles. I also have a few sponge filters as well. In my opinion, there are pros and cons to anything. If you chose 2 HOBs, you will obviously have double the maintenance, so that may be a drawback. As for the 110, it is a great filter, but here are my personal drawbacks:

1) It pushes alot of water. Maybe too much. With small fish in the tank, the outflow force can really push them around. The adjustable flow really doesn't change much.

My solution for the above: I find that if I lift up on the intake tube of the 110 just slightly, it slows it down enough, and softens the fall of the water. I also placed a large Co-op sponge filter under the outflow, with a pretty tall uplift tube (Not the one that comes with it.) This really helps diffuse the downforce of the outflow, and also adds to more spread out surface agitation. Side note: The uplift tube I use actually goes around the bullseye circle of the sponge filter, instead of inside of it. Since its internal diameter is wider, it makes for a wider column of bubbles, which I like far better for it's purpose. It also helps to prevent stray bubbles from exiting the sponge portion of the filter.

2) I like symmetry, and it slightly bothers be to see a huge HOB on just one side of the tank. It it a big filter and takes up alot of horizontal real estate.

In short, I think I would go with 2 55's if I had it to do over again. (Possibly even a single 75). But the 110 really is a fine filter. Your mileage may vary. Good luck!

 

 

[Nick L]

For the record I had a tidal 55 and I used it on my 29 gal... I know it dosent help your sizing question but I will say that the tidal was super easy to set up lasted a long time (that tank isnt set up anymore and the filter is in storage right now) but the brand really impressed me. The aquarium co-op youtube channel has a few videos on sizing your filter and how much filtration you really need that ive found really helpful. Hope this helps 

[FrozenFins]

if you place two 55s at the two ends of the tank it will cause more flow which is good and is probably what I would do. For asthetic reason I like filters at one end of the tank, especially sponge filters. Angelfish are the best, you chose a great fish.

Edited January 18, 2021 by James Black
typo

[Janelle]

@Nick L I have been reading up on the tidal filters and I am really considering that brand!  I am a little concerned however w/ the built in skimmer as I want to add in livebearers and wonder if that would be problematic for the fry.  Any thoughts or experience?

[Janelle]

9 hours ago, quikv6 said:

Hey Janelle,

I have a 110 Aquaclear on a 75 gallon Molly/Platy tank with lots of fish, mostly juveniles. I also have a few sponge filters as well. In my opinion, there are pros and cons to anything. If you chose 2 HOBs, you will obviously have double the maintenance, so that may be a drawback. As for the 110, it is a great filter, but here are my personal drawbacks:

1) It pushes alot of water. Maybe too much. With small fish in the tank, the outflow force can really push them around. The adjustable flow really doesn't change much.

My solution for the above: I find that if I lift up on the intake tube of the 110 just slightly, it slows it down enough, and softens the fall of the water. I also placed a large Co-op sponge filter under the outflow, with a pretty tall uplift tube (Not the one that comes with it.) This really helps diffuse the downforce of the outflow, and also adds to more spread out surface agitation. Side note: The uplift tube I use actually goes around the bullseye circle of the sponge filter, instead of inside of it. Since its internal diameter is wider, it makes for a wider column of bubbles, which I like far better for it's purpose. It also helps to prevent stray bubbles from exiting the sponge portion of the filter.

2) I like symmetry, and it slightly bothers be to see a huge HOB on just one side of the tank. It it a big filter and takes up alot of horizontal real estate.

In short, I think I would go with 2 55's if I had it to do over again. (Possibly even a single 75). But the 110 really is a fine filter. Your mileage may vary. Good luck!

 

 

Thank you!  I don't have experience with the flow of each size HOB so that is some good info.  

[Janelle]

29 minutes ago, James Black said:

if you place two 55s at the two ends of the tank it will cause more flow which is good and is probably what I would do. For asthetic reason I like filters at one end of the tank, especially sponge filters. Angelfish are the best, you chose a great fish.

Thank you for the feedback!  I am excited about the Angels 😃

[Nick L]

13 minutes ago, Janelle said:

@Nick L I have been reading up on the tidal filters and I am really considering that brand!  I am a little concerned however w/ the built in skimmer as I want to add in livebearers and wonder if that would be problematic for the fry.  Any thoughts or experience?

We raised shrimp with ours and did have a bit of a problem with the duckweed getting in the skimmer at first. But there is a controll dial that worked well for us that basically put all the flow to the underwater intake not the skimmer, we also used nylon stockings (panty hose) and a small plastic zip tie to keep any small fish shrimps or snails out of the filter, there would be some that managed their way in from time to time, but that was usually when the water was high in the tank we think they were climbing in the outflow instead of getting sucked up through the inlet. I will say the maintenance peg on the lid stuck a little bit so you have to kind of watch out for that. But it was a really sturdy and quiet filter. Well worth the money in my opinion. I haven't tried out too many other hob filters but I'll take one of those over anything that has a cartridge system any day

[Janelle]

39 minutes ago, Nick L said:

We raised shrimp with ours and did have a bit of a problem with the duckweed getting in the skimmer at first. But there is a controll dial that worked well for us that basically put all the flow to the underwater intake not the skimmer, we also used nylon stockings (panty hose) and a small plastic zip tie to keep any small fish shrimps or snails out of the filter, there would be some that managed their way in from time to time, but that was usually when the water was high in the tank we think they were climbing in the outflow instead of getting sucked up through the inlet. I will say the maintenance peg on the lid stuck a little bit so you have to kind of watch out for that. But it was a really sturdy and quiet filter. Well worth the money in my opinion. I haven't tried out too many other hob filters but I'll take one of those over anything that has a cartridge system any day

Good to know!  I hate the sound of water splashing into the tank so a HOB was my last choice.  I was going to go with a canister - but after watching many videos of Cory explaining why they shouldn’t be your go to it finally sunk in. And then I was reading the Aquaclear tops rattle. 🤪🤪  I major in the details of life so setting up my 1st aquarium is taking a bit of time to work through alllll the options!

[Nick L]

You could also look at doing an over top diy sump (lots of videos on how to and pretty cheap) you could build your own. Or a few days ago chewy (the online pet store) was running massive sales on canisters (I dont think Cory would mind canisters so much if they were priced alot better lol) I got one rated for a 30 gal tank for 30 dollars those arnt on sale right now but on chewy.com or the app theres a marineland  360 gph canister for about $115 and a 220 gph for about 85. Theres alot of diy canisters online too if you. Or you could drill the tank if you really wanted to and do a sump

[Mansoboy]

I have 2 fluval C4 in a 44g long and it is definetly enough. Have both of them installed in each side, at half of the flow rate. The hob output level is at same level of the water, this way I avoid water splash sound and flow disrupts well water surface for oxigen exchange.

In every WC I clean one filter (just the prefilter sponge and interior sponge).