pH control

[Zafgak]

Hi Guys OK this is going to be a long one so hang in there --- :bigsmile:

I posted this in "my little pH project thread" and was thinking last night ??

What I didnt mention was buffering. Anyone out there with experience in chemical control of pH want to make some suggestions .....

Firstly the good news - I have just purchased a lab grade pH probe and amplifier - the price : R770-00 for the probe and R550-00 for the amp.. For a lab grade setup this is VERY cheap and I will happily pass on details on where to get them ex Jhb.

The reason I bought it is for the "Famous Fish Room" which will be a thread by Veegal (My Georgeous wife) starting tommorrow.

What I propose to do is fairly simple. Take a 100 litre drum of water, next to that take a 20 litre drum. Put the pH probe in the 20 litre drum and add about 18 litres de-chlorinated water. Stir gently. Add acid slowly ( using a piece of air pipe and an electrically controlled valve ) and let the pH instrument control the acid dosing valve. This way I can set the pH required and control it to 2 decimal points or better. When the pH is at the required value (can be set anywhere) pump the water into the 200 litre drum and repeat until there is 200 litres of the correct pH water. This is then circulated to all the tanks, and new pH correct water is made up when needed.

I recently completed a project at work for a pharmaceutical lab that was growing "Bugs" to make vaccines. In that project I had to keep the water at 37 degrees +_ 0.2 degrees, pH at 7.15 +_ 0.05, Dissolved oxygen at 98% ( This varied quite a bit as the bugs grew and used up the O2 ) and we kept a watch on Optical density (How clear the water is) to monitor how well the bugs were growing.

So keeping a constant pH is relatively easy if you have half a million rand to throw at it. The trick is to do it at home for as little as possible. What I am trying to do is get correct pH water at the least possible cost. So far I am in for the cost of the pH probe and amplifier. Add the cost of the tanks and the control valve and I am hoping to get away with about R2000-00 all in.
I have access to a controller so that cost I am saving..

If anyone wants details of this system and how to go about it give me a shout Ill be happy to pass on what I know.
http://www.tropicalaquarium.co.za/images/buttons_mns/quote.gif (http://www.tropicalaquarium.co.za/newreply.php?do=newreply&p=4271)

[TyroneGenade]

What I propose to do is fairly simple. Take a 100 litre drum of water, next to that take a 20 litre drum. Put the pH probe in the 20 litre drum and add about 18 litres de-chlorinated water. Stir gently. Add acid slowly ( using a piece of air pipe and an electrically controlled valve ) and let the pH instrument control the acid dosing valve. This way I can set the pH required and control it to 2 decimal points or better. When the pH is at the required value (can be set anywhere) pump the water into the 200 litre drum and repeat until there is 200 litres of the correct pH water. This is then circulated to all the tanks, and new pH correct water is made up when needed.

What are you keeping that needs such precise pH? I've kept and spawned angels. Apistogramma, Betta, various killies, Malawis, Lake Victorians, Tanganyikans, tetras, barbs etc... and have never even owned a pH test kit nor given it much thought.

Joergen Scheel did an experiment with killifish where he moved individual fish from one tank to another where only the pH differed. He could move fish from pH 6 to pH 8 and vice versa without any problems. What did cause trouble was moving them from one total-dissolved-solids concentration to another. The most the fish could take was a 50% change up or down and then you got problems. pH is mostly irrelevant unless you are a bacteria (because bacteria cease to convert NH3 to NO2- at a pH below 6) and an immuno-compromised Discus (remeber! bacteria can't grow well below pH 6 so if the pH rises above pH 6 the bacteria can party in stressed fish).

I have even spawned Discus in the horrible conditions of a pet store. All we ever did was feed them and do a 50% water change (straight from the tap, no dechlorinating, nothing). The pair would spawn like clockwork the next day, and provide a feast for the other fish in the tank. :evil:

Quit worrying about pH. Rather spend the money on good food for the fish. Well fed fish are happy fish and happy fish spawn and resist disease better.

[Zafgak]

Hi Tyrone and thanks for the comments - I am an engineer and therefore have to play with things :idea:

I may never get around to doing it I was throwing my thoughts to the forum to see what people would think. Generally we have no problems using good old CT water.

I was just considering if you had a fish that was very finicky this would maybe be the way to go.