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Is it the Volume or Water or Size of tank that matters?

2K views 16 replies 6 participants last post by  Nubster 
#1 · (Edited)
Is it the Volume of Water or Size of tank that matters?

I'm on the very first stage of considering a larger tank for my fish, but the issue is i have a very specific area i can keep it in that limits the footprint i can use...

This tank will end up being for two fancy goldfish, a Redtop Oranda and a Black Moor, i have read that length of tank is more important then depth for goldfish, but i'm wondering does volume of tank matter?

Basicly the Largest i can go footprint wise would be 37wide by 13 deep....

Within this footprint, there are:

Gallons.......................Width x depth x height
26 Flatback...............36 1/4 x 12 1/2 x 16 5/8
23 Long...................36 1/4 x 12 5/8 x 13
30 Gallon.................36 1/4 x 12 5/8 x 16 3/4
38 Gallon.................36 1/4 x 12 5/8 x 19 3/4
45 Gallon.................36 1/4 x 12 5/8 x 23 3/4

Given "perfect Filtration", why would the 45 gallon be better then say the 23 Long?
 
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#2 ·
Well I would think volume would matter just as much as size when it comes to goldfish. I know the 23 long is just as long as the 45 but I wouldn't but that many fish in the 23 as the 45 due to the volume issue or not as much room so to speak. If that makes sense. I would go with the 45 if it was me.
 
#3 ·
With the tanks and footprint you have listed, they all have just about the same foot print so the gas exchange is going to be the same. The only thing you can control is the volume. The greater the volume, the more water you have to dilute waste products.

I would go with the largest volume tank for the area. My favorite tank is the 40 breeder 36x18x16 but that is just outside your listed footprint.

Dilution is the solution!
 
#6 · (Edited)
The reason i ask is i currently have filters that (are rated to) turn over the my current tank water 24x an hour...so the water is sparkling...even if i go with the 45 i'd be over 15x an hour...

Given Perfect filtration, or atleast filtration to the level i have it...does volume matter, i can't figure out why it would
This is an example of how "filtration" (referring to the filter equipment) is somewhat irrelevant in ascertaining the actual health state of the water.

Filters move water through media. The more this occurs, the clearer the water should be, relative to other things obviously. But clear and clean are not the same thing. A tank can be crystal clear but the water can be highly toxic to any fish. And similarly, the water may be opaque with cloudiness yet be so clean the fish are as healthy as they can be.

Looking at the clean aspect, filters can only go so far. They function biologically with respect to the nitrification cycle. But there is much more to clean water than the ammonia, nitrite and nitrate. There is what I term "crud" that no filter can remove. Dissolved waste, urine, pheromones released by fish, chemicals released by plants... all this crud remains in the water no matter how many or how good the filter equipment. And the more fish or larger fish, the more crud. Goldfish produce a lot of this, which is why they need relatively large tanks.

Crud only gets removed via a water change. So back to your question about volume: the more water in the tank, the less quickly crud will build up. And again, the filter has absolutely nothing to do with this. Now, it does impact via the biological side, because the crud is impacting that too. But the initial crud is still there until you remove the water. The smaller the tank with more fish, the more frequent and larger the water changes must be. This is the water quality aspect of tank size. The physical aspect, namely providing appropriate space for the particular fish to be themselves, is related but distinct.

Byron.
 
#7 · (Edited)
So the Crud factor we can't test for (Unless thats TDS) what would you say would be the difference in the required Water Change schedule on a 45 gallon tank with two fancy goldfish vs a 23 gallon tank with two fancy goldfish to clear the 'crud'...i thought the sponges, polishing pads, carbon and purigen were for cleaning crud? i thought just the bio-media was for the actual nitrofying bacteria

I have TONS of DE available that i can use if that'll help with the crud?
 
#12 · (Edited)
Lets go with the units he used in the article, generically called pollution units, in this case we'll go with a number of 10 pollution units per goldfish...just to make it easy...the average goldfish tank is recommended as 20 gallons for the first fish and 10 gallons more for the second....with 10x the tank volume in filter per hour, and weekly 50% water changes...we would assume the recommendation is that way because it cleans the tank

So two goldfish would put out 20PU, in a 30 gallon tank that would be .66PU per gallon, a 50% water change would reduce that to .33PU per gallon with the 10x filter per hour(.033 per full tank cycle) further reducing that to 0PU

Now lets do those number with my equipment and a 23 gallon tank...

Two Goldfish still product 20PU, in a 23 gallon tank that is .86PU per gallon, a 50% water change on weds reduces that to .43PU(its too complicated with two water changes) now my filters run about 700GPH, so that is 30x the tanks volume an hour, and we've established that recommended specs pull .033 per cycle) that means my filters now filter out .99PU's from the water in an hour...That leaves me with NEGATIVE .56PU's in my tank

Lets try this math without water changes(i'd never not do water changes)
two goldfish 20PU, 23 gallon .86PU per gallon, .033 per cycle with 30 cycles = .99PU, it is still Negative .13PU
 
#15 ·
Honestly? The Goldfish are my daughters, although she only lives with me every other weekend and three weeks over the summer.....But because of the height of the stand i have...and her being 6....she has alot of trouble feeding the fish when she's here, although she loves them and is hardly away from the tank when she's here...we have a stool we use, but its a fight to get her not to use the tank to 'pull herself up' and i don't want to have to yell at her everytime she's over daddy's...having the tank as made a big difference in the struggles to have her leave mom's house...i'm trying to keep it as enjoyable as possible for her

A shorter tank would make a HUGE difference....so i'm kinda trying to justify something shorter then the current 19" tall tank i have now
 
#16 ·
So I realize that this may be taken as me stepping into a parental area that I do not belong, but I honestly don't mean it that way. I'm not trying to butt in, promise! I'm just thinking that maybe there's a way to work this out so everyone wins, fish included. So, some thoughts... maybe you could get the bigger/taller tank, and try alternate routes with your girl. My little girl uses a step ladder, and I have her put her hands on the top of the ladder as she climbs on. You could even mark the hand spots in her favorite color paint? Or with stickers? Or you could have her climb on a desk chair and, while holding her securely, roll her to the tank. (Of course, you'd have to keep holding her as long as she's on the chair.) Or could you fashion a place where she could safely put her hands that isn't on the tank? Like a broomstick or something that's been placed at about the height of the tank rim but is secured to the walls or tank stand? Or just lowering the stand, either by modifying the legs of it, or using a different stand? Since she loves the fish so much (which is adorable), maybe if she understands how her actions could hurt the fish, she'd try hard to be careful of her hands. I don't know, just some thoughts. :-D My "Aquarium Assistant" is 7 years old and, like you, I'm so glad we have this hobby together! Good luck!
 
#17 ·
Do you already have the goldfish? I may have missed that if you do. If not...you may consider a different fish or group of fish that would work better in the smaller tank. I understand now why you are trying to make the small tank work...it's a tough balance trying to do whats best for your little one and the fish.
 
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