Ph Controller?

[Lord Fishheart]

Looking to start keeping discus next year anybody use a PH Controller for their discus tank?

 

[Colin_T]

PH controllers are normally used on plant tanks that have CO2 added to them. You can use them on discus tanks but most people don't bother. Unless you are keeping wild caught discus, it isn't worth the hassle or money trying to modify the PH. Captive bred discus will tolerate a wide range of water conditions, with locally bred stock being more tolerant than imported stock.

 

[plantbrain]

pH controllers can use buffers to control pH.
Few aquarist bother.

Most use CO2 gas to lower pH.

However, this does not help fish in any way, "stable pH = better" is pretty much a myth near as I can tell as far as fish, plant health etc. They use CO2 gas to fertilize the plants, not to stablize the pH.

Some get confused and parrot what someone else that does not know much about plants and fish says.........then you get a hard to kill myth.

What causes changes in the pH without adding CO2? Buffers, baking soda will raise the KH, CaSO4(gypsum) and MgSO4(epsom salt) will raise GH. The GH plays no role in pH stabilization, KH does.

KH is mostly HCO3-, some plants can use this as a form of carbon like the plants that use CO2. Aquatic plants adapted to this for good reason, in higher density, aquatic plants remove all the CO2 and their growth is limited, then some will go after the KH.

If you want a stable pH, you can use baking soda to add KH. Discus etc are not happy with higher KH's in general, I've not seen any issues with higher GH however..........same for plants.........

So you can use PO4 buffers to lower pH range without adding baking soda and more KH. This is artifically lowering the pH without CO2. You should never use pH lowering chemicals with planted tanks and CO2 however.
Folks mix up pH and what KH is and how/what CO2 is used for in aquariums a lot.

If you do routine large water changes on a Discus tank, use lower KH water, say 3 degrees or so, perhaps less if you wish, then do not bother with pH at all.

I do not suggest folks use a pH controller on planted tanks.
There's no need to add CO2 at night and if the KH changes, then reading and dosing will be off(as is often the case).
It's better to place the dosing of CO2 in the hands of th aquarist.

Simply turn the needle valve a bit more or down etc to control, the valve will control the rate very well, and a solenoid will add CO2 only when you need it, during the light peroid. Plants do not need CO2 at night, nor do fish need higher levels of CO2 then either (14 hrs). During the day when CO2 is added, the plants produce a lot of O2 and also consume the CO2 that's being added.

This means that fish are generally okay respiring out CO2 and taking up O2 during the day, more plants, faster growers etc, the more O2 is produced and the more CO2 demand there is from the plants. At night, the plants do not produce O2, nor consume CO2, so don't bother adding it.

Also, make sure to have some decent current, just like a normal tank without plants etc, while O2 is produced from the plants, most is still coming in from above, some folks go wayyy too far trying to conserve their CO2 and choke their fish in the process(particularly when you combine high CO2+ low O2). Then they get algae since they are scared to add enough CO2 and complain pH controllers appeal to those who know less about CO2 and it's use in planted tanks, like techy solutions, equipment, have more $ than experience. Some buy them and later learn they are not that useful and then keep them. CO2 and Kalk reactors is another thread, but like the CO2 use in planted tanks, it's really about Ca and KH in the reef. Not pH directly. Same deal with CO2 in planted tanks, it's about CO2 for plants, not a particular pH. Many folks use the pH/KH table to deterimine CO2, but that KH part can mess you up if it's not all HCO3-. Tap water often has PO4 buffers for corrosion etc. Poor calibration etc, probe falling out, near electric fields can cause really bad errors and add lots of O2 into the tank all at once.

Needle valves are very stable.
Stick with those.

Regards,
Tom Barr

 

[xxBarneyxx]

For discus I would recommend getting an RO unit and then mixing the RO water with your tap water until you get the desired results (in terms of KH). As mentioned as long as you do regular water changes in this way your PH & KH should remain pretty stable.