Minimum ratio between fish inch/kg & surface area sq ft filter media?


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I know most of us try to do more then needed in filtration but just wanted to know What is the minimum ratio recommended between fish in inches/kg and surface area sq ft of filter media ?
and whats the difference in calculation if koi fish is fed once , twice or thrice
if circulating water once an hour

5 inch fish per 10 sqft surface area , or 15kg for 100 sqft is it true?
 
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Neither is true and both are true. You hit on some of the factors, but there are many more. Which is why these internet ratio schemes are just numbers pulled out of thin air. It's actually pretty easy to correctly size bio to fish load....measure ammonia. If you need more bio then ammonia levels will increase but normally not so fast you can't deal with as more bio is brought online.

And better yet, if you understand the relationship between ammonia and ammonium and how water temp and pH move ammonia and ammonium you have an ever bigger safety net.

That's the only for sure way. Everything else is a bit silly.
 
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Neither is true and both are true. You hit on some of the factors, but there are many more. Which is why these internet ratio schemes are just numbers pulled out of thin air. It's actually pretty easy to correctly size bio to fish load....measure ammonia. If you need more bio then ammonia levels will increase but normally not so fast you can't deal with as more bio is brought online.

And better yet, if you understand the relationship between ammonia and ammonium and how water temp and pH move ammonia and ammonium you have an ever bigger safety net.

That's the only for sure way. Everything else is a bit silly.

I get u sir, suppose some one is starting new setup whats the ratio to begin with ? as cycling and growing of bacteria takes time and it cant be checked before adding fish load so there should be some guideline and preparation, if results are bad after system starts cycling we can increase media i understand that but that will take time too . for bacteria to grow and process water . .
 
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I can give the basics, but kind of a lot of typing, even for me, to give full explanation.

Virtually all "ammonia test" you read about in pond forums are a "Total Ammonia" test, ammonia (NH3) and ammonium (NH4+).

These 2 chemicals do something interesting. As pH and/or temp increases NH4+ converts into NH3. As pH and temp decreases NH3 converts into NH4+. So with a Total Ammonia reading AND the pH AND water temp you can calculate the amounts of NH3 and NH4+.

This is all important because only NH3 (ammonia) is actually harmful to fish, while NH4+ (ammonium) is safe (as long as pH and temp don't change).

Why this is important...seen this many times in pond forums. "Experts" will tell new pond keepers to screw with pH and never mention ammonia. New person increases pH and fish start getting into trouble and none (and they do like to pile on) of the "experts" know why. Many of the things tossed into the pond then make ammonia testing difficult so more confusion, more crap tossed into the pond. Finger generally gets pointed at the new person..."they must have done something wrong. I raised pH in my pond and fish were fine". A person does one thing one time and thinks it's proof of something. Cornerstone of internet thinking.

The ammonia ammonium relationship in most ponds isn't really super important in many cases especially when the pond keeper is serious about bio filtering. This is because the bacteria (and other critters) that convert ammonia and ammonium consume KH so these pond owners normally keep KH high which keeps pH high and stable. Once you get above say 8.5 pH then NH3 (ammonia) is going to be a big part of Total Ammonia so that test can be good enough. I've seen pond keepers who use KH measurements to understand how their bio filters are working, but that should only be an indicator imo.

Sometimes in the spring people test Total Ammonia, get a highish result, freak out and dump all kinds of stuff into the pond causing serious problems when there never was an actual problem because water temp was so low that harmful NH3 was actually low.

With proper bio filtering both NH3 and NH4+ is very low. (we say zero but that's not actually possible). Knowing the relationship between NH3, NH4+, pH and temp helps understanding which leads to achieving the goal. And also test how much actual bio conversion a pond has. For example, say you have 3 barrels of bio media...is that 10x more than you need and you're safe or do you have just enough and tomorrow ammonia will start creeping up? In both cases a zero ammonia reading doesn't tell you. So you can take one barrel off line and measure ammonia over a period. If ammonia creeps up you know you don't have 10x. A serious person can keep doing this until they have a good idea of how much ammonia their filters can handle roughly. Understanding NH3, NH4+, pH and temp means you can do this testing safer, so NH4+ creeps up and not NH3.

Of course all this has little use in Water Gardens where bio filter isn't normally needed. This stuff is what owners with Koi ponds packed with large fish have to do to keep the herd alive. Most Water Garden keepers who add something they refer to as a bio filter just think it looks cool and assume it's way good.
 
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I get u sir, suppose some one is starting new setup whats the ratio to begin with ? as cycling and growing of bacteria takes time and it cant be checked before adding fish load so there should be some guideline and preparation, if results are bad after system starts cycling we can increase media i understand that but that will take time too . for bacteria to grow and process water . .
Same answer as before, sorry. Ratios are just made up stuff.

It can be checked before adding fish, absolutely. Isn't uncommon in ponds where the plan is to add a bunch of big Koi right off. Ammonia is added to the water to get up to a high level, but not so high the converters can't live. The keeper then charts the lowering of ammonia, and maybe the nitrite cycle. That tells them when the bio filtering is ready for fish to be added. Some people pee into their pond instead of using ammonia.

Another way it's done is waiting for the water to turn green. Again, ammonia and/or other nutrients might be added too. Once starting to turn green the fish can be added and the algae will consume the ammonia. Bacteria aren't the only consumers and in most Water Gardens I suspect algae is #1 by far. Even when cycling a bio filter credit might go to algae but a keeper will assume always assume it's their creation.

Another way is to dump in some fish, maybe small younger fish, and watch ammonia and a few other parameters. Ammonia is allowed to increase, and knowing NH3 vs NH4+, they know when safe and when action is needed. If NH3 gets too high they do water changes (always a plus anyways) to lower and add ammonia binder if really needed. They manage the ammonia until converters are up to speed.

The most common method is to dump in the fish and have a beer, or glass of wine, and never measure anything. This works very well. It is extremely rare for people new to Water Gardens to over load a pond on day one. Normally the problem starts to happen much later as fish grow, muck accumulates, filters are never cleaned, new fish are added or reproduce. Even then weaker fish will die and ammonia will be handled that way.

Also, ammonia converters can come up to speed very fast when conditions are good. Nitrite converters are a bit slower.
 
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That's about a good a guesstimator as any. And if a person is hell bent on using such things they could do worst.

But still, they're trying to sell filters. Sounding like you know what you're doing helps. The converter critters are living creatures and lots of critters grow inside bio filters all in a war for life. Many things determine what critter does well and how well. For a filter seller to say filter X handles Y amount of fish mass is...well...pretty made up. Looks impressive though.
 
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I have always used with success 1 inch of fish per 1 sf of surface area, but that is for a decently filtered and airated pond and fish averaging 3-5 inches. My last pond had 60-70 Sf of surface area and my fish never exceeded even with babies 60-70 inches but again that's with smaller fish. You could have one 10" fish that could have more weight than 100 1 inch fish.
 

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I have always used with success 1 inch of fish per 1 sf of surface area,

The flaw in this frequently advised method is that it does not take into account depth. In a pond 2 feet deep, this equates to 1" per 15 gallons of water, but in a pond 4 feet deep the ratio becomes 1" per 30 gallons of water. A very inaccurate method of determining fish load.
 
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And 1" of fish in a 24" Koi is about 1/3 lb while for a 4" Goldfish 1" = 4/100 lb. So that's only off by a factor of 8 or 9. How wide is the US? About 300 miles if you don't mind being off by a factor of 8 or 9.

And then there's the other dozen factors... Yeah, ratio estimates, just one of many pond myths. Thank you internet.
 
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Of course these are rough guides for a beginner to use such as surface area to fish size or pond volume to bioload. They need to start somewhere and to me this is the easiest way to understand a pond can hold only so many fish and not to overload it. I think most beggining pond people way exceed these rough guides so something is better than nothing. Of course for an experienced person they would not use these but for my little pond in the past the formulas have been helpful so I don't keep buying new fish when I think my pond is at it's max bioload!
 

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