How do I adjust the pH downward

[sandyc]

I received an order rotifers today and am preparing the water to release them into. The directions say to adjust the pH of my water to that of the rotifers. Unfortunately, it does not say what to use to adjust the pH. I checked on the suppliers web site and there is a link for information about adjusting the pH unfortunately, it isn't working right now. Can anyone tell me what to use to take the pH from 8.4 to 7.2?

[MCsaxmaster]

These are brackish rotifers, correct? Assuming the answer is yes, the pH in their water is low due primarily the build-up of CO2, as would be expected in a sealed container during shipping. You could use CO2 (e.g., from a CO2 cylinder, or seltzer water) to lower the pH of your water prior to releasing them. This will help prevent shock when transferring them to the new water. The excess CO2 will degas over time and the pH will slowly rise back to normal.

Alternatively, you could acclimate the rotifers to the new water somehwhat like what you'd do with new fish.

[sandyc]

Yes, they are brackish rotifers. Thanks for the help. I do not have CO2 or seltzer water on hand. I will have to run out and get some. Could I just SLOWLY add water to the rotifers (drip) like I do when I acclimate a new fish?

[MCsaxmaster]

<a href=showthread.php?s=&postid=13104055#post13104055 target=_blank>Originally posted</a> by sandyc
Yes, they are brackish rotifers. Thanks for the help. I do not have CO2 or seltzer water on hand. I will have to run out and get some. Could I just SLOWLY add water to the rotifers (drip) like I do when I acclimate a new fish?

Yep, I would just acclimate them like one does with new critters going into a tank. Dripping in water is a fine way to do that.

Aerating their water would also drive off CO2 and raise pH closer to that of the tank, but would also affect the speciation of ammonia/ammonium in the water. At low pH most of the ammonia occurs as ammonium (NH4+) which is essentially non-toxic. At high pH we see mostly ammonia (NH3) which is toxic at high concentrations. Hence, I would suggest it is better to dilute the water they're in with clean water and simultaneously raise pH, just as is done with fish and other critters.

Chris

[sandyc]

Thanks Chris.

[MCsaxmaster]

:thumbsup:

[tmz]

Regarding ammonia speciation, won't just opening the bag cause the ph to rise as CO2 equilibriates wtih the air and to rise even more during a long acclimation, resulting in prolonged exposure to the toxified ammonia?

I know CO2 or seltzer is best here but in a pinch could a bit of vinegar if available be used with minimal risk for a bacterial bloom?

Generally, when I recieve shipped fish or critters I adjust the qt tank to the bag water when I know it's parameters before opening the bag and then quickly place the organisms into the qt minimizing the time they spend in air exposed bag water. Most shippers will tell you ph and sg. Floating the unopened bag in the qt can adjust temperature.