Water Changes & Filter Maintenance

[mark4785]

I was just wondering what people refer to in order to establish when a water change is needed? I've seen many people stating that they conduct weekly/bi-weekly water changes, but why? I test my nitrate, PH, KH and GH levels several times a week and when one of these parameters start to go excessively high or low, this is an indicator for me that a water change is needed. A week has passed so far and none of these parameters are reaching dangerous levels, so do I really need to stress the fish by doing a 20%+ water change?

I've been told that without water changes, a build up of decaying matter can occur causing an ammonia/nitrite spike. Each week I syphon the gravel once or twice to remove any possible trapped detritus. I have sand so it's very hard for their to be a build up of larger matter underneath smaller granules of sand. Is a syphon sufficient enough to stop an ammonia/nitrite spike?

Lastly, do you refer to the outflow of water from the filter to determine whether cleaning of the filter media is required?

I'd appreciate all of your opinions on this matter.

Thanks,

Mark.

 

[Tolak]

Gut instinct really. Tanks stocked really heavily will get 75%+ weekly, fry tanks may get 50% daily, lightly stocked tanks may get 50% every other week, or 25% weekly, depending on what is in there. I haven't tested water in years, beyond dipping in a TDS meter if I'm working with ro. If something seems off, change water. Changing water is pretty stress free compared to a fish's natural environment. Between often living on the edge of starvation, getting chased by larger predatory fish & such water changes are minimal stress.

The waste produced by fish is acidic. Prolonged lack of maintenance will drop the pH of the tank water. Ammonia is less toxic at lower pH levels, the colony of nitrifying bacteria is smaller at lower pH levels. When a water change is finally done the pH rises, the ammonia the fish are producing is more toxic, the bio filtration takes a while to catch up. In a poorly maintained tank the hardness & TDS will also increase, when water is changed this hardness decreases. This is what causes problems for fish, often attributed to a change in pH. A double whammy of sorts, fish has difficulty eliminating waste due to osmotic pressure, and ammonia that was once able to be handled by the bio filtration is not. Nobody vacs in the wild, the accumulated debris is often measured in feet, there is a constant supply of fresh water. Natural debris in a tank is a breeding trick.

The output of a filter as a measuring gauge for cleaning depends on the filter, as some do have a bypass for when the media begins to clog.

 

[waterdrop]

Wow, excellent write-up! We need to get you out of the tank-room more often WD

 

[mark4785]

Gut instinct really. Tanks stocked really heavily will get 75%+ weekly, fry tanks may get 50% daily, lightly stocked tanks may get 50% every other week, or 25% weekly, depending on what is in there. I haven't tested water in years, beyond dipping in a TDS meter if I'm working with ro. If something seems off, change water. Changing water is pretty stress free compared to a fish's natural environment. Between often living on the edge of starvation, getting chased by larger predatory fish & such water changes are minimal stress.

The waste produced by fish is acidic. Prolonged lack of maintenance will drop the pH of the tank water. Ammonia is less toxic at lower pH levels, the colony of nitrifying bacteria is smaller at lower pH levels. When a water change is finally done the pH rises, the ammonia the fish are producing is more toxic, the bio filtration takes a while to catch up. In a poorly maintained tank the hardness & TDS will also increase, when water is changed this hardness decreases. This is what causes problems for fish, often attributed to a change in pH. A double whammy of sorts, fish has difficulty eliminating waste due to osmotic pressure, and ammonia that was once able to be handled by the bio filtration is not. Nobody vacs in the wild, the accumulated debris is often measured in feet, there is a constant supply of fresh water. Natural debris in a tank is a breeding trick.

The output of a filter as a measuring gauge for cleaning depends on the filter, as some do have a bypass for when the media begins to clog.

So, if I conduct a water change BEFORE fish waste induces a more acid PH level and BEFORE I notice the total dissolved minerals rising, this is a good indicator that I'm not stressing the fish? I say this because if I did have a acidic PH and an excess of dissolved minerals, adding fresh water would induce a massive change in these parameter values and consequently stress the fish, right? So I guess the key is to provide many small water changes.

 

[OldMan47]

If you wait for a pH drop, you have waited way too long for water like mine. My water can buffer an awful lot of acid before the pH will move at all. At one time I was a person who tried to establish "ideal" pH for my fish and I went through an awful lot of acid with no results that lasted more than a few hours.
I also go by feel but back that up by watching for a flow drop in some filters and sometimes check on myself with a nitrate measurement to make sure I am not getting a big build of nitrates.

 

[Tolak]

That all depends on the stocking, the tank size, tank water parameters, the parameters of the replacement water, and how often you are doing water changes. Prolonged lack of tank maintenance is usually measured in months in an average stocked community tank, weeks in a heavily stocked/overstocked tank.

In these cases, yes, smaller 10% daily water changes for at least a week will slowly get the fish acclimated to the parameters of the local tap water, after that a more sensible maintenance schedule can be followed.