Added Nilsen reactor, now have high pH

[bean3178]

I added a DIY Nilsen reactor to my tank last night. I was at the point where I noticed my calcium beginning to drop and I was also having to add Superbuffer dKH every 3 days to keep my alk up. My pH has always been fine in the 8.2-8.3 range.

This morning, my pH looks a little high. Probably around 8.4. Do I need to worry? Is there anything I should do to get it back within "comfortable" limits?

Right now, when my auto top-off system turns on, it replaces the evaporated water with limewater within just a few seconds. I'm going add a ball valve to the RO/DI output to slow that down a bit. Will that make a difference?

[Randy Holmes-Farley]

High pH is one of the limitations to using limewater. I wouldn't worry about the pH unless it rises above 8.5. Mine is usually in the 8.3 to 8.5 range.

If the pH gets too high, more aeration can bring it down, along with cutting back on the lime delivered (by stirring less often). You can also bring it down with soda water or vinegar.

[bean3178]

Thank you very much. It's a relief to hear that my params are still acceptable (since my pH has never been that high). One last question:

Will the kalk drip speed affect the water params? I plan to slow mine down anyway since it dumps in 1-2 cups at once when the auto top-off soleniod opens. Just curious.

[Randy Holmes-Farley]

If you add limewater too fast, the pH will rise. If the pH rises too much,you can begin to precipitation calcium and alkalinity as calcium carbonate, reducing them somewhat (or a lot if the pH really gets high).

[bean3178]

I'm going to go ahead and add some vinegar to bring down the pH a little until I can get things stabalized. Any idea how much I should start with (105 gallon tank)? 1 cap full, 1/2 cup? I just want to bring down the pH a tad. I'll be more careful with the top-off rate and will monitor pH closely.

[bean3178]

Update (hopefully this will help someone else in my situation):

I think my pH crept up as high as 8.5-8.6 today. I added 2-4 teaspoons of vinegar at a time over a period of a few hours. My pH is now back to normal levels. My inhabitants seem fine so far.

I put a ball valve on my auto top-off, which will slow the addition of the top-off limewater when it is on, and cause smaller amounts to be added more frequently. I set up the mixing pump to turn on for 5 minutes every 2 hours between 8pm - 8am. From 8am - 8pm, the pump turns on for 10 minutes every 4 hours. This should create a more potent dose during the night.

We'll see what happens in the morning. I'll continue to update this thread.

[AuContraire]

Watch for an algae bloom with the addition of acetic acid/vinegar. I tried the vinegar approach for 3 days and saw hair algae growth in locked step with each ml of vinegar added. If you decide to try soda water, please post your results in this thread. I have not heard from anyone that has tried this approach and am curious.

[Randy Holmes-Farley]

Soda water works fine. A teaspoon per gallon of tank water will drop the pH by a few tenths of a pH unit. Start with less to be conservative. Maybe 1/2 or 1/4 teaspoon per gallon. Exact measurement is tricky as it is bubbling and losing potency as it is measured out.

Vinegar is trickier as much of the pH drop happens later when bacteria consume the vinegar and produce CO2. A couple of teaspoons for a 100 gallon aquarium is a fine place to start.

[bean3178]

Well, I added more than a coupe teaspoons. Probably about 15 total. I just woke up this morning, so going to test the water now.

[bean3178]

Okay, this morning we have:

pH: 8.3
KH: 10
Ca: 420

So, everything looks good for the short term. Now, let's see how the Nilsen reactor helps over the next few days. I'll keep this thread updated.

[Randy Holmes-Farley]

So far so good. :)

[bean3178]

Another update:

Params have been fine since the initial scare a day ago. I added more kalk to the Nilsen reactor this morning. I came home at the end of the day today and noticed the pH was high again - it was showing at 8.6 on my Salifert test kit. I added 3-4 teaspoons of vinegar to the tank. I also put 2 teaspoons of vinegar in the Nilsen reactor hoping that would lower the lime water pH a bit. Wish my digital pH monitor would hurry up and arrive. Calcium is good at ~440 and alk is good at about 10-11.

[Randy Holmes-Farley]

How often are you stirring the reactor? Maybe stir less often to deliver a little less lime.

[jdieck]

If your problem contiues you may need to buy a doser pump so you can add the Kalk in a more steady and continuous way and be able to add less that the evaporation although you can; Randy say try to add a Kalk mix that is less concentrated by stirring less frequently and for a short period of time.

[bean3178]

It stirs for 5 minutes every 2 hours from 8pm - 8am. It stirs for 15 minutes every 4 hours from 8am - 8pm.

I've noticed that the pH has been higher immediately after I've refilled the Nilsen reactor. I'm wonder if some of the pickling lime got into the tank or if a super saturated dose got added when I add the cap back onto the reactor. After all, it's added from the top of the reactor, near the water line to the tank.

[bean3178]

Everything is fine again today. I added some vinegar last night to lower the pH a bit. I think it's only happening when I refill the reactor. It's still only been a few days, so there hasn't been enough time to develop any trends yet.

[jdieck]

For what is worth I only stir three times a day for 1 minute.

[Randy Holmes-Farley]

Everything is fine again today.

OK, great. Happy reefing. :)