An insight into low pH, ammonia and understanding the role of kH

Hi All,

Over the past years I have eagerly been reading up on articles, blogs and forums regarding the effect of a low pH and I wanted to share the topic with the MFK crew.

I want to bring this to peoples attention as I had to battle this in my early stages of fish keeping. After constantly getting readings of 0.25 - 0.50 of ammonia, 0 nitrites and 20-40ppm of nitrates I was struggling to come to terms with why I would have any readings of ammonia? Before going any further I will give everyone an overview into my setup.

The setup -

Tank: 180gal

Filtration: 3ft sump with 5ltrs of scrubbies, 2 ltrs of substrat pro, 2 ltrs eheim bio rings, japanese mat and other bio mats along with an Eheim 2260 full of substrat pro and eheim rings.

Stock: 4 silver dollars and 4 juvenile peacock bass.

Maintenance: weekly 30% water changes

At the time I assumed that if my tap water was reading 7.0 then my tank water would automatically sit at 7.0! Logical one would think no? Well - no. What I missed was the hardness and being a noobie I didn't really understand kH and the role it plays so neglected it. I neglected to check the pH and kH. Once I was lost for answers I went back to basics and tested all my parameters and found a very low pH of 6.0 and kH of around 50...could of been lower but tests don't show lower then 6.0. - After alot of research and investigation I found the below possible theories and the solution


The general scenario:
A tank with a low pH of 6.0 (maybe even lower as test kits only test to 6.0) is very soft water and thus there is not enough hardness (kH) to hold a higher pH of neutral or alkaline level. Tanks with a low pH will find constant levels of the non-toxic form of ammonia (NH4)

The Theories:
1) Low pH does not support the growth of beneficial bacteria. It is believed that BB is present however cannot combat the break down of ammonia into nitrates and thus never removing ammonia indefinitely (assuming water changes are done weekly). Even with constant water changes there will always be a trace of ammonia in the NH4 form. This is said to be non-toxic to fish however any change in pH levels may turn this into NH3 which is harmful ammonia and inevidibly into nitrite which is a real killer.

2) Beneficial bacteria cannot survive in a low pH tank thus ammonia is not broken down but again is in the non-toxic NH4 form. This does not mean that fish are safe as a lack of maintenance can easily result in the build up of of nitrites that WILL kill fish. There have been cases where no matter what effort was made with water changes and filters the level of ammonia (NH4) has never dropped below 0.25. Conditioners such as Prime can give a false reading of ammonia (NH4) - ensure to have a test kit for ammonia to test for the NH3 form only - not both.

My situation was this - Australian tap water, in the state of Victoria, does not have a good level of kH to support a neutral pH level thus hobbyists are having to add kH boosters or crushed coral to level the pH. I never checked the kH level of my tap water and found that even though my tap water had a pH of 7.0 the night after a water change my water would still read a level of 6.0.

Since then, I have added crushed coral to permanently maintain a pH level of 7.0 which has in turn dramatically improved the growth of BB. The higher kH presence has also sustained the healthy colonies of BB that breaks down ammonia into nitrates. This process eliminated all levels of ammonia - both NH4 and NH3

I encourage others battling with their tank water similar to my situation above to check ALL parameters as this may help you as it did me.

If you find yourself in a similar situation - it is advisable to raise pH slowly to a neutral level as a quick rise can result in a tank spike. Please be aware that if you choose to use crushed coral to bare in mind that crushed coral works by breaking down into the water thus raising the pH so it is advised to watch levels of coral and replace whatever diminishes over time to sustain the desired pH level

Hopefully this will assist others to a healthier fish keeping lifestyle as it did for me - even if it only helps out one person then I am happy to of put this together

Any comments and modifications are most welcome

Hasi

squint;4028663; said:

I found that ammonia is still kind of toxic < pH 7 so I now opt to keep my tanks at higher pH even if the fish prefer slightly acidic water. I have to check pH regularly because I have soft water and add pure baking soda as needed. I use an electronic pH meter with an ISFET probe and calibrate it regularly. The old school pH meters drifted a lot and I don't like chemical pH tests.

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Great response Squint.

Thanks for pointing out that ammonia is quite toxic at a pH greater then 7.
The ideal setup though, at pH 7-7.5, is that there is enough media and filtration to support healthy BB colonies to combat and break down ammonia where in an established tank should read 0 ammonia. The only present parameter should be nitrate that can be minimised and controlled with constant water changes


It is also worthy to note that having a low pH and non-toxic ammonia present the fish are likely to be lethargic, less active and sensitive to disease such as Ich and Cloudy eye - I cannot confirm these are true however I can vouch that fish are less active and lethargic with these conditions and you can really notice the difference in character once fish are in ideal conditions ie growth, food consumption and colouration

squint;4029205; said:

My clown loaches were breathing heavily, had possible red or dark looking gills and shredded fins so I began to suspect that ammonia wasn't as non-toxic as it was said to be at a pH < 7.0. Then I opted for a pH > 7 so the biofilter would work more efficiently and process the ammonia rather than trying to render it harmless with a low pH. Results have been a lot better with a pH > 7.

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Squint - I think from both our experiences it is safe to assume that regardless of whether the ammonia is non-toxic at a low pH, it still is not natural environment for fish to live in and if you want your fish to thrive then a pH of 7.0 is recommended (depending on species obviously - we are going by rule of thumb)

batang_mcdo;4029468; said:

thanks for sharing this information, I've also had propblems 2 years ago with ph crashes and cycling. every time my tank shows nitrite , or shows progress in cycling, myph crashes back to 3-4 , Out tapwater kh here is 2.
i've had to add lots of crushed coral into my tank to keep ph stable.

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Glad to hear it batang_mcdo - that is what these forums are for. What is a lesson learned if it isn't taught?

Here is a very well constructed conclusion to an article on water chemistry with a low pH and hardness

Close: should you bother with pH and hardness?
Categorically the answer to this question is simple: fishkeeping is a lot easier if you keep fish suited to your local water conditions. Nothing trumps the ability to perform large-scale water changes on a regular basis, and if all that entails is swapping out old water for dechlorinated water taken from the mains supply, so much the better. If you live in a hard water area, then choose hard water fishes: livebearers, Central American cichlids, and Rift Valley cichlids are all ideal fish for such conditions and offer the aquarist lots of opportunities in terms of size, colour, behaviour, and breeding.
In a soft water area South American cichlids and tetras, Asian barbs and rasboras, and gouramis all make good choices. While soft and acidic water aquaria are not without their problems, these can be easily side-stepped if you simply perform large and regular water changes to pre-empt any potentially dangerous pH changes.
If you&#8217;re lucky enough to have water that&#8217;s only moderately hard and around neutral in pH, then consider yourself lucky: you have the most versatile sort of water and will be able to keep and enjoy a very wide variety of species.

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Link to article http://www.wetwebmedia.com/FWsubwebindex/fwh2oquality.htm