My salt mix has higher DKH than my tank...How do folks deal with that?

[RussC]

I use RedSea Coral Pro salt. Coral pro salt mixes to a DKH of 11.8. Not really where I want my tank to run. I run my tank as close to 9 DKH as possible. Tank seems very happy at that level. My system water volume is about 100 gallons. Every two weeks I do a 20 gallon water change and that 11.8 new water jumps my DKH up about .6-.8 DKH. Over the course of the next two weeks it will gradually drop back to about 9 +/1. But then its time for a water change and the cycle repeats.

I've been really focused on dialing in my alkalinity with my dosing pump to get a very steady DKH and have gotten pretty darn close. But every two weeks when I make a new batch of water it changes. Anyone have this issue? Any suggestions?

Sitting here typing this something occurred to me. What about a 10 gallon water change every two weeks. In theory that should cut the increase in DKH in half. Less impact. Closer to consistent. I really would prefer to stay away from a weekly water change schedule.

I had a minute, thought I'd zap this to the world and just see what folks thought. Feedback? Thoughts?

 

[mcgyvr]

So...
Either you just leave it and lets say you want your tank to be at 8dkh and your fresh saltwater is 12dkh.. The day before your water change your alk is now 7.0 dkh due to consumption over the course of the whole week and your 20% water change with 12dkh water brings it right back up to 8 dkh again.. All is good..
This is partly why many salt mixes are much higher than people normally maintain their tanks at.. because if you are relying on water changes to keep your levels stable (not dosing yet) then you need new saltwater to be higher to that it can bring the levels up to where they should be..


Or if you are dosing now then you just use muriatic acid to lower the alk of the freshly mixed saltwater to the level you wish to maintain your tank at..
The formula is floating around here somewhere..
A search for "muriatic acid alkalinity formula" should get you there..

 

[RussC]

I have fooled with the muriatic acid just experimenting a little when I overdosed on alk not long ago. Never put that experimental water in the tank but the acid certainly did the trick. I know it also changes the ph and its important to aerate things to recover the proper ph.

 

[Scott07]

Just went through this a few months ago. If you choose to go the muriatic acid route mcgyvr described here are a few things you should know:

Muriatic acid is a name for a specific dilution of hydrochloric acid... somewhere around 35%.

Muriatic acid/hcl are dangerous. Wear PPE and research best handling practices if you need to.

Big box store muriatic acid off the shelf is allegedly ok to use from my research. Reagent grade, 37%, hcl can also be obtained online from many sources. Search for 'the science company'. That's where i purchased my bottle.

The formula mcgyvr described is:
New Saltwater dkh - Desired dkh x Volume of New Saltwater (gal.) x 0.123 = required dosage of muriatic acid to achieve desired dkh.

I use right around 4ml. to lower 16 gallons of freshly mixed reef crystals to about 8.1, 8.2 each week when i mix up water.

 

[RussC]

Good info. That might be an option I consider.

 

[hkgar]

I use a CA reactor and make sure the salt mix has a lower dKH. I use the standard Red Sea salt mix.

Here is a good guide

 

[JWClark]

Or, if you have room, just set up automatic water changes. That’s how I got over it—and I didn’t want to remove alk then pay for adding it back with dosing. I have two brutes next to the tank hooked up to a ghl doser. One has fresh salt water (IO w/ added Ca and Mg) and the other gets waste water. I drain one and fill the other every theee weeks and the doser does small changes every 15 minutes for a total of 10 gal per week. And when I get new stuff the waste water is used for QT tanks.

Would look better if I actually put in a cabinet. On the other side of the rank is the third brute for auto top off.

 

[Daddi0]

Just use the Red Sea in the blue bucket