7 replies to this topic

[mtchye]

OK I thought I'd bring up the subject that is often misunderstood in the hobby... the issues of water hardness, pH, and buffering capacity can be confusing, but is really very simple.

Hardness can be divided into general hardness (gH) and carbonate hardness (kH). gH refers to the amount of calcium and magnesium ions in the water. The more ions in the water the greater the conductivity, hence you may sometimes see people refer instead to conductivity as a measure of the ion content of water.

Carbonate hardness refers to bicarb or carbonate ions in the water. These help 'buffer' the water against changes in pH. Basically this means that if something happens that will change the pH of your tank's water, it will happen much faster in a tank with low kH (and hence low buffering capacity) than in a tank with heaps of carbonates in the water and thus a high kH.

Some fish eg those from environments where the water is mainly fresh rainwater and there are lots of rotting leaves etc prefer a water with very low hardness. They are also often more resistant to very low pH levels. You can reduce pH and hardness levels for these fish using various methods if your water is hard, one easy way is via peat filtration, and others include reverse osmosis.

Others such as those from the rift lakes prefer hard waters with higher pH, and dont tolerate pH swings as well, especially swings into very low pH levels. If your water is low in gH and kH, you can buffer it by adding chemical compounds that will increase the levels of calcium, magnesium, and carbonate ions in the water.

A lot of you guys keep african cichlids. Some are successful using no buffers at all, some use limestone (which slowly dissolves increasing the water's hardness) or coral substrates, some add premixed manufactured 'african salts', and others make up their own chemical mixes.

Lets hear how you guys have done it, and it would be especially interesting if you have changed from one method to another and seen a difference..

Now theres a topic.. ! Now i hope to see many responses. Doesnt matter if you know squat about chemistry, just let us know what you do, any problems/advantages, and how you have gone with different methods!

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[CommodoreKev]

On the subject of water quality, how much filtration does every one run. I've seen some tanks running with basically a small sponge through to setups with major water turnover. Is too much filtration as bad as not enough, or is it the more the better?

[mtchye]

Hi Kev, Good question!

In most cases when we talk about filtration we are refering to the capacity of the filter to convert ammonia into nitrite, then nitrites into nitrates. The amount of ammonia that the filter needs to convert will affect how much surface area the media in the filter needs to have, and how much of the water in the tank is passed through the filter in a given period of time.

So, the amount of filtration needed in a tank depends on how many fish there are in it, and how much food you feed those fish, as this will affect the amount of ammonia in the water that needs to be converted.

Most people over filter, to provide for a margin of error. If you have a filter that is just adequate for your needs, what if you add another fish, or feed more, or a fish dies and starts rotting? In those circumstances its better to have excess capacity in your filter to take more load.

The type of filtration will affect how efficient your filter is as well. Trickle type filters where the water trickles down through the media and is mixed with air seem to be very much more efficient than filters that are totally submersed. I use several such filters which consist basically of a box that sits on top of the tank, with water pumped up there by a powerhead, and gravity pulling the water back down.

The type of media also affects this. Basically you want to get media that has as much surface area as possible, but doesnt get clogged too quickly. Stuff like the clay pieces have micropores that mean that there is greatly increased surface area for bacteria to colonise, but these pores quickly get filled with gunk, meaning you have to replace it at set times to keep the filter running at its best. Thats why people go for bioballs, open cell foam, and japanese matting, the combination of surface area and ease of maintenance.

Another factor is how many plants you have in the tank. Plants will uptake ammonia and nitrates. If you have a heavily planted tank with fast growing plants, you can sometimes get away with little or no filtration. (and even have to add nitrates sometimes)

I don't think you can have too much filtration. The only down side would be if you had too much current in the tank for the type of fish that you keep. Otherwise you can have a gigantic barrel canister filter for your little 2 ft tank and it wouldnt hurt it, as long as the current in the 2ft isn't too much.

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[CommodoreKev]

Cool, so if in doubt about the filtration level it is ok to add a bit more. My new tank has an internal trickle, so i will see how it goes. Do you need to run an air stone in the trickle?

My main tank a 4 x 2 x 2 has about 40 fish in it, it's running a eheim 2028 and a eheim 2012 in it, which I assume is enough for that load. I'm not too worried about the other tanks as I will not be stocking them as much.

Thanks..

Kev

[mtchye]

Kev, trickle filters in general also add lots of oxygen into the water due to the large surface area of the water exposed to air, so in most cases you probably won't have to add an air stone into the trickle.

Depending on your fish load however, you may have to add an airstone to agitate the water in your main tank. Just watch for fish that are 'gasping' for air. An airstone in the main tank also serves to break up any oily films that may be impeding the gas/water exchange.

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[Brett in Perth]

Hi all,

I would generally agree with mtchye that for the vast majority of tanks you can't have too much filtration.

I think an exception is a heavily planted tank with low fish load. Do any of us keep these!! If strong plant growth is desired then conserving CO2 in the water is important and excessive surface agitation results in loss of CO2. Wet/dry filters are particularly efficient at lowering the CO2 in your water. Also many forms of chemical filtration will remove trace elements from the water that are required for good plant growth.

I know this is a cichlid board, but some of us try to grow plants

[mtchye]

Hey Brett,

Yes I keep several planted tanks with minimal filtration. In these tanks conserving CO2 is usually a must, and makes the use of trickles/biowheels and other such filtration methods not suitable.

You are also right about some forms of chemical filtration removing trace elements.

There are a few of us that grow plants
Not many though...

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[oo fish styx oo]

Well I HAVE plants...... don't know about actually growing them.....