RO/DI Water Treatment Questions

[Craig731]

I've been having an issue with ph and mix up water recently. I've taken my aerated/heated RO/DI water, mixed salt, a teaspoon of Osmo-Prep (trace and calc buffer) and then needed to add in more Kent Buffer to raise the alkalinity to the correct levels.

However, by the time it's in the right range, the water is now cloudy and reading a ph of 8.8. Is there some trick or something I'm missing in how to properly get the alk up on RO/DI water?

Or should I just salt and mix in trace elements and play with the alk in only the display?

Also for top-off water, should anything at all be added?

[kevin2000]

My 02

In most cases you should not have to add calcium or alk to your newly made saltwater ... I suspect every major salt mfg comes within reasonable specs.

If you are determined to adjust your salt then I would suggest you make sure your salt is "aged" before you do any testing or adding .. this will insure the salt is throughly dissolved and has been aerated to allow the PH to properly adjust. If you feel you need to adjust then I suggest you don't add alk supplements on the same day you add calcium supplements .. may cause precipitation issues and you may end up with less of both.

[AZDesertRat]

A good salt mix should not need anything else added. Some are lower in Alk like Oceanic while others are low in Calcium like Instant Ocean. pH will not be stable for some time thats one of the reasons most people will recommend mixing up yuor water 24 hr ahead of time.

[der_wille_zur_macht]

To answer your second question, you should not be adding anything to the topoff water unless you specifically need it. In other words, you do NOT need to adjust the topoff water to certain parameters, since it's purpose is to replace 100% pure water lost due to evaporation.

However, topoff additions are a common way to dose alkalinity and calcium supplements, specifically kalk solution. The important thing to understand is that you're just using the topoff water as a tool to deliver the supplements, not trying to adjust the topoff itself. The real key is monitoring and controlling the parameters in the display tank.

[Craig731]

Thanks a lot for the replies

[mr_o98]

I would worry about stabilizing the parameters in the display rather than the top-off. PH takes a full 24 hours to stabilize.
When I mix new salt water, I let it sit for 2-3 days before I do a water change. That way everything is stabilized before it is added to the tank.