Pond Boss Forums GENERAL QUESTIONS Water chemistry proper water chemistry

can anyone tell me what would the optimum water be?? i mean what ph do you shoot for and what alkalinity etc.?? i have looked on this site and have read alot of discussions, but have not found an answer to my question. also what do each particular measurement mean.

Big Bass, optimum is an elusive term when we apply it to water in lakes or ponds. I like to think that each pond has a natural chemistry that is many times more dominant than most human interventions to that particular ecosystem. The chemistry of a pond is dominated by the particular soil, plant life, fish life, runoff, depth, rain pollution, etc. A pond that is managed for aesthetics will have a different chemistry than one managed for trophy bass, or for firewater, etc. Unlike the inert (most of the time) environment of a swimming pool where you can dial in the chemistry (pH of 7.4, alkalinity of 200, chlorine 3-5ppm...) and get a predictable outcome, the plant and animal life present in a pond will impact the chemistry on a daily basis. pH can change in a pond from a low of 6 in the early morning to a high of 11 in the mid-afternoon. If we have a cloudy or rainy day this dramatic change won't happen. In fact the lack of an "optimum water" is probably what makes this forum so interesting.

There are some general principles such as pH ranges of 6.5 to 9 are good for fish production. Below 4 and above 11 forget fish. High oxygen levels are in general good. Below 4ppm forget bass; below 3ppm or so, forget catfish.

I like to view the measurement of the physical and chemical properties of the pond water as a tool to troubleshoot departure from a base case. The delta of the property, I feel, is more important than the absolute value of that property. For example, that the turbidity of your pond has increased by a factor of 2 is more important than indicating that the turbidity should be exactly 8 NTU's (Nephelometric Transfer Units). This may be an indication that your grass carp has eaten all of the available vegetation and is now nibbling at roots and stirring up a bit of the hydrosoil...

Finally, each particular physical or chemical property measurement of the water in your pond has a meaning as they relate to what you are trying to achieve. For example, if your lake is quite clear, this means that the bass will be able to easily see their forage prey. However, if the water is too clear, it is unlikely that you are getting any algae blooms that are sustaining your food chain and soon there won't be any forage for the bass to see... I am assuming the you are not asking for the meaning (definition) of a property such as pH being the -log[H+] in solution...etc.

Above all, Big Bass Hunter, you must identify the goals of your fishery. Your "ideal" water chemistry may be different depending on the species, size, and density of the fish you would like to see predominant in your particular system.

Think of it as "Basslow's Hierarchy of Needs". Meaning, fish need in the following order--

1. wet
2. oxygenated
3. appropriate temperature
4. ability to forage for and capture appropriate prey items.
5. spawning conditions

Once you identify your goal, a biologist or member of this forum can give you a range of conditions that favor your desired goal. Let me emphasize the word "range". There is no exact pH, DO, water temp or salinity for a species but if you can keep your pond's water chemistry in the best "range" for the greatest possible time then your fish can use his energy towards growth instead of emergency survival.

Answers above are right on the money. To simplify, pH range from 6-9; oxygen, never range below 4 ppm; alkalinity >20 ppm. The bottom line...water is an amazing substance, with outstanding qualities and a wide range of acceptability for fish and plants. Different species have different requirements. That's a key reason different environments provide diversity.