View Full Version : Raising Alk too fast???

03/07/2013, 08:06 AM
My Alk has been perpetually low for a while now and getting it to move up has been painfully slow to this point. I'm going to be doing about a 20% water change this weekend, and my thought is to really boost the Alk in the replacement water to see if that can get me moving in the right direction.

Right now my Alk is about 6 to 6.5 dKh. I have a 120 gal tank with about a 30 gal sump and obviously a lot of water displacement by rocks and equipment. I'll be doing about a 20 gal water change this weekend and I was thinking about adding enough baking soda to the change water to bring it's Alk up to around 12 to 15 dKh. I'm just wondering if this is a safe way to boost the Alk more quickly as I've been adding about 6ml per day of the Kent dKh buffer for 2 weeks now with only bringing Alk from about 5.8 to 6.4 in that time.

Thanks in advance for any feedback.

03/07/2013, 08:26 AM
I believe normal or recommended alk is 7-11 dkh and if you raise alk it should be done very slowly, no more than 1.4dkh per day. I would not plan on raising your alk with your water change. How is calc normal and your alk so low? I use dosers from brs and if you go to there site they have a calculator that will tell you how much to add to reach your desired levels. Definitely wait for more advice before doing anything. What are your other parameters and what kind of livestock do you keep?

03/07/2013, 08:28 AM
dont increase by more than 1dkh a day is my suggestion. if you hare having trouble keeping it up make sure mag is in check

03/07/2013, 09:19 AM
When I need to raise my alk I just throw some baking soda in the sump. Or add it to your topoff water. Use this (http://reef.diesyst.com/chemcalc/chemcalc.html) calculator to determine how much (I only raise mine 0.5 dkh per day).

Once you get it where you want it, you can switch over to kalk to keep it there.

03/07/2013, 09:45 AM
+1 on the advice above. Don't raise over 1.5 dKH per day and then not all at once like w/ a water change. Do it slowly by increasing whatever you are using to dose thru the dosing system. You know what you are doing is not meeting demand so increase the regular dose to bring into line for tank consumption and then supplemental dosing by doubling up on the Kent to 12ml till you get back over 8.0 dKH and then just let the dosing pump do the work over time. Be sure to test daily while dosing the Kent and after you reach target goal to make sure the dosing system is in line w/ consumption.

Merry Skerry

03/07/2013, 10:08 AM
Don't try to raise your ALK with just water change. Water change is okay for trying to maintain your levels, but you will be wasting a lot of salt if you are trying to raise it up. The easiest would be get a 2-Part and dose the ALK portion and as others have said, don't raise too much at once.

03/07/2013, 10:25 AM
I agree with everyone else's comments so far. First, raising or lowering anything, especially alk, rapidly will have detrimental effects on your tank. Remember, stability is key to healthy coral and a happy tank. Everything you do to change parameters in your tank should be done very slowly. Rapid changes could result in tissue loss, STN and RTN. I had probably a 2dkh swing over a couple days and some of my more sensitive corals started to STN/RTN. Second, having alk around 12-15dkh is way to high IMO. Natural sea water is around 8-9dkh. ULNS' require even less then 8dkh, between 7-8dkh. Some people I have read run there tank around 11-12dkh, but I start noticing ill affects on my tank around 9.4-9.8dkh in the form of STN. Where ever you do end up with you levels, just remember to go slow and maintain it once your there.

03/07/2013, 11:03 AM
I'd probably shoot for 8 or 9dkh and raise it 1 dkh per day with cabonate/bicarbonate premixed in ro/water as part of the top off. You could add it dry to a high flow area. Measuring the salt mix and accounting for the alk in it plays into the level as well. Mixing a lot of carbonate with the salt mix might cause precipitation in the new salt water ; dilution will be greater in the larger tank water volume.

03/07/2013, 01:29 PM
Thanks for all of the great feedback. I'll probably just check the Alk of my change water to make sure that it's not low to begin with. I figure to set my change water to maybe 8dKh as I know that this will raise Alk of the tank from the approximately 6.4 it's at right now but nothing dangerous.

As far as the other parameters... I'm not sure how things got so out of whack, but I started noticing an outbreak of red slime and so I checked my parameters, which I had been rather lax on lately, when I discovered my Ca and Mg were both reading off scale high and Alk was down around 5.0 dKh. At that point I immediately stopped adding Kalk to the ATO and did a 25 gal water change. Slowly I have seen the Mg come down from over 1600 to about 1520, and the Ca is now back on the scale at about 485 from over 500. This is also when I began adding the dKh buffer and have brought up Alk about 1.5 dKh over the past couple weeks.

I'm definitely wanting to switch over to the baking soda recipe for Alk as that's going to be a LOT more cost effective. For now, I'm planning on adding the baking soda to the ATO to slowly boost Alk over time, and keep an eye on Ca and start the Kalk back up when it gets down to about 450.

04/29/2017, 07:55 AM
I know on the redsea liquid B suppliment it says not raise dkh more than 1.4 per day, does this mean if your tank depletes 1.4dkh per that you can add 2.8dkh to compinsate for the depletion?

04/29/2017, 12:32 PM
Yes, that should be fine, although I probably would do that in two doses, one in the morning and one in the evening.