Confused by Alk Reading

GoGoGeeba · Jun 20, 2016

Ok so within last two weeks I purchased my tank from a neighbor. Tank was in good condition. Since then I have done two water changes totaling about 20%. I just purchased the Red Sea Alk,CA,MG test kit. My calcium has fluctuated and I think that is most likely due to me learning how to use the test. It's ranged from 500-400. The magnesium has varied too and again I attribute that to learning the test. My problem is the alkalinity. It has consistently stayed above 14dKh. I'm sure most people are familiar with the Red Sea Test. Well I tested it today about two hours after water change and I had to use 1.15 ml to get the blue to turn red. So it is still over 14. I don't know how to lower it or get it to come down. Any help would be great.

AdamNC · Jun 20, 2016

As soon as you see there is no more blue in your vial, the test is done. If your trying to get it as red as the pic on the card is then you may be putting too much tritation in. I usually stop just as the last bit of blue is gone and then one more drop for good measure. Your color could be pale yellow, slight pink or a slight orange. According to Red Sea that is acceptable. My first test kit was pink but the past 2 test kit refills have been orange.

GoGoGeeba · Jun 20, 2016

Are you supposed to stir it as your dripping? I can see the red start to show at the bottom, I swish it and it goes away. No color change whatsoever until after 1ml has been dripped.

AdamNC · Jun 20, 2016

Yea after every drop or two I'll swirl it. If no color change and your that high then just let it drop naturally and not add any more alk until your where you want to be. It is possible you could also have a defective reagent. See if you can get a second opinion at your LFS or purchase another brand kit as a backup like Salifert.

Rob Lion · Jun 20, 2016

Practice with test kits makes perfect.....
Also..... double check your salinity... than needs to be correct first or it will affect tests...
lastly, as a double check, if you cant get a salifait test kit etc, you can do the test based on using just 50% tank water with 50% RODI (0 TDS) added to weaken the solution, then you should see the colour change happen a lot sooner... you can double the result to get your actual reading.

If you readings are all correct, don't panic, just don't dose any additives and let the dkH come down naturally by what the tank life is consuming.

Test Alk every day! its a great indicator to how your tank is doing

cmcoker · Jun 20, 2016

Are you using a pH buffer? If so stop, despite label claims they alk raise alkalinity

GoGoGeeba · Jun 20, 2016

I haven't dosed in about 4 days because it was so high...I though for sure a water change would have lowered it. I'll just leave it for now and see if it goes down.

Randy Holmes-Farley · Jun 21, 2016

GoGoGeeba said:
Are you supposed to stir it as your dripping? I can see the red start to show at the bottom, I swish it and it goes away. No color change whatsoever until after 1ml has been dripped.

Yes, that is the correct way to do a titration.

The color changes locally because there is extra titrant (the added liquid) in a smallish amount of the test liquid, and it seems the endpoint is reached, but only where the liquid was added. When mixed in, it then is diluted and you are no longer at the endpoint.

Many salt mixes are close to 14 dKH, so it may just be you have not depleted it much yet.

Also, are you using tap water? Tap water can add alkalinity, both in top off and in making new salt water.

shadow1013 · Jun 21, 2016

I normally wait a day before testing after a water change to make sure everything has mixed. You can watch the video red sea did on their youtube page if that helps.

GoGoGeeba · Jun 21, 2016

Thanks guys. I get water from a lfs and i checked the salinity and its at 1.020 so i have to add reef crystals. I'm switching where i get my water so hopefully that'll help. I will check out the video...didn't know they had one

GoGoGeeba · Jun 22, 2016

Ok another question lol, I'm going to get my water tested by another lfs. I don't really have any corals in the tank that would use alk. Would it be on if I add 1 or 2 to bring it down

Randy Holmes-Farley · Jun 22, 2016

I don't understand the question. At this point I would not add anything to bring the alk down, or do super sized water changes.

AdamNC · Jun 22, 2016

Wait for the Alk to naturally come down to at the very least 12dkh, preferably 10dkh.

BoneXriffic · Jun 22, 2016

Reef crystals is designed to replace alk right? If i am not mistaken doesnt it add a higher alk value to a water change than regular IO?

AdamNC · Jun 22, 2016

RC has a higher content of Alk, Ca, Mg and trace elements than IO.

GoGoGeeba · Jun 22, 2016

Thanks guys. I will just let it fall on it's own

BoneXriffic · Jun 22, 2016

Start using regular io in my opinion for changes

Randy Holmes-Farley · Jun 22, 2016

BoneXriffic said:
Start using regular io in my opinion for changes

FWIW, normal IO also has high alk.

Red Sea normal (blue) might be a good choice if you want a lower alk mix.

BoneXriffic · Jun 22, 2016

Randy Holmes-Farley said:
FWIW, normal IO also has high alk.

Red Sea normal (blue) might be a good choice if you want a lower alk mix.

Did some research and it seems reef crystals is just a slight bit more calcium. Alk, mag all about the same. If this is true reefcrystals is kind of a rip off

Randy Holmes-Farley · Jun 23, 2016

BoneXriffic said:
Did some research and it seems reef crystals is just a slight bit more calcium. Alk, mag all about the same. If this is true reefcrystals is kind of a rip off

I prefer normal Instant Ocean and used it for 20 years because I'm not a fan of the organics added to Reef Crystals.