Water change schedule

[Partha007]

Between Water change schedule- 10% every 10 days versus 30% monthly, which one better for a fish-only tank?

 

[Lasse]

As you can see 10% every 7 days will give a little bit better water in average than 30% every 30 days. I have also put in a daily WC of 1.4 % and 3 % as comparision.

Sincerely Lasse

 

[Partha007]

As you can see 10% every 7 days will give a little bit better water in average than 30% every 30 days. I have also put in a daily WC of 1.4 % and 3 % as comparision.

Sincerely Lasse

How will the graph l

As you can see 10% every 7 days will give a little bit better water in average than 30% every 30 days. I have also put in a daily WC of 1.4 % and 3 % as comparision.

Sincerely Lasse

How will the graph look like for 10% every ten days?
What schedule of water change(amount and interval) may be a balance for reduction of pollutants, efforts on the part of aquarists and no sudden big changes in water chemistry?

 

[Lasse]

In a only fish tank - the chemistry is not very critical but I think that a daily WC between 1 and 3 % would be the perfect balance of all three things you mentioned. It can be set up automatically. Answer to your question

How will the graph look like for 10% every ten days?

With this graph

Sincerely Lasse

 

[dmiller212]

Super interesting graphs and info!

 

[Raamish14]

As you can see 10% every 7 days will give a little bit better water in average than 30% every 30 days. I have also put in a daily WC of 1.4 % and 3 % as comparision.

Sincerely Lasse

I’m thinking to do one every 30 days for my two clowns in a fowlr tank and then an extra one every now and then to reset everything back down. But then again 2 clowns won’t even make 1ppm a day for me. I give them 8-10 pellets total a day.

 

[Lasse]

the 1 ppm was only an example and it was chosen because it is easy to extrapolate—for various inputs —how many ppm of different substances are added to the water column via feeding. The "status quo" level (where the amount removed by a water change equals the amount added through feeding) is determined by the level of the input. The smoothness of the curve, as well as the point in time when this status quo is reached, are determined by the frequency and the percentage of the water change.

Note that these curves apply to a "fish-only" aquarium with little or no growth of photosynthetic organisms. If there is a significant population of photosynthetic organisms, the curves will show a lower "peak" and reach the status quo sooner—read regarding inorganic nutrients (primarily PO4 and the NH3/NH4/NO2/NO3 complex)—because there is an additional factor, beyond water changes, that removes these substances from the water column.

Sincerely Lasse

 

[Lasse]

Some ideas how much one gram of aquarium pellets food will contribute with to the water column (adult fish) Pellets normally contain between 40 to 50 % protein. Let us say 45 %. This means that it is around 0.45 g of proteins in normal pellet food. Around 16 % of this is N - it means that around 0.07 grams of pure N will enter the aquarium. Average uptake (into fish biomass) of N is around 20% which means that 80% of added N will end up in the aquarium - which means that around 0.06 g inorganic N will enter the aquarium in worst case. If all of this will end up as NO3 - it means that around 0,27 g NO3 per gram pellets food added. See the graph below in order to understand how much this is in mg/L (nearly equal to ppm in this case of low concentration) for different volumes of aquarium water. I´m living in Europe - I am not entirely comfortable working with systems other than the metric system—consequently, calculation errors may occur. Please let me know if you spot any miscalculations. I use the conversion 1 gallon = 3.79 liters, and 1 ounce = 1/28.35 of a gallon (rounded to two decimal places).

NO3 concentration ending up in a Fish Only aquarium in different feed regimes (dry food) and aquarium sizes. If you use only wet food (frozen natural food) - divide the figures with around 7

The same with PO4 - dry pellets contain around 1 % P. This means that around 0.01 g pure P will enter the aquarium for each gram added. With the same formula for primary bio-accumalion (fish biomass) around 0.008 g P will enter the water column with every 1 g of dry pellets added- corresponding to around 0.024 g PO4

Importen to mention is also that the rise of the N species is rather fast after the addition - after a couple of hours is around 80 % of the N not needed for fish biomass excreted through the gills as NH3/NH4 and in a well function aquarium - nitrification happens more or less directly. With the P - its different - the not needed P is normally excreted by the pop and need som bacterial treatment before it released into the water column. With the PO4 - its also important to mention that the graph above reflect a mature aquarium where the binding capacity of PO4 into gravel and stones has reach its balance point. In a young aquarium - much of the added PO4 will be bound in gravel and stones.

As with the NO3 - if you use frozen natural food - divide the figures with around 7. However sometimes frozen foods can be polluted with extra PO4. Its sometimes used as a preservative.

Sincerely Lasse

The graphs above its not carved into stones – there are variations in every aquarium – view these as a guide to how it might turn out