Excess Demand for Alkalinity in Saltwater Reef Tank - Solution
Reef tank 8 years ago 10,432 views
In this video I talk about the issue of a reef tank consuming more alkalinity than it is getting while at the same time not using any calcium. The solution to this problem is not visible in that you can't simply add more ALK to remedy the problem. In fact, if you do this it makes the problem more pronounced in some cases. Im dosing equal 2 part ALK & CA, so normally we see a reduction in both ALK & CA. With the tank consuming more Alkalinity than calcium, I knew better than to change the settings on my Apex so that my dosing would add more alkalinity to supplement what I was loosing and then also reduce my calcium because I wasn't using as much. The reason you dont want to do this is that if you dose more of one supplement, and less of the other, you end up chasing numbers because adding more of one supplement (CA or ALK) reduces the other. This leads to great instability in a reef tank. ALWAYS dose equal parts of ALK and CA, no matter what, when dosing two part. If you have to make a correction in your levels, boost your levels in your tank with product to get your levels back into the ideal range, but always leave the dosing settings equal. (ppl who use kalkwasser dont have to worry about this because Klak is a balanced supplement.) The solution to my problem of the reef tank consuming more Alkalinity, and hardly consuming any Calcium, was that I needed to reduce my inflated levels of magnesium. Here is the article that talks about this issue: http://www.reefkeeping.com/issues/2004-12/rhf/ Once my magnesium levels dropped to normal levels, the tank started to slowly fall back into stability. The tank was now using both alkalinity and calcium again.
So ya the mangrove trees explains a lot :)
mg 1470. cal 550 kh 8.0 and so yesterday I started to look at my levels and now they are cal 530 mg1410 and kh 4.1!!!! soo I ended up here that you for posting this video
Don't add buffer. Use straight sodium carbonate (not bicarbonate). Better test kits would help a lot if you're using API. How many gallons is your tank btw?
10. comment for Excess Demand for Alkalinity in Saltwater Reef Tank - Solution
Generally you want to keep your DKh as tight as possible, and you are correct - 8.2 to 8.4 is not a huge swing. But I think what you are not seeing is that the tank slid all the way from DKH 9. At 8.2 I felt it was time to take action.
Thanks! Glad it helped. This stuff is tricky sometimes.
You're correct. The Log book is basically a "business journal" I found at Staples. It has lines running left to right and I just add the vertical lines for how many columns I need.
I use Salifert Tests for the Magnesium and Calcium and a Hanna tester for the Alkalinity. I find the Hanna tester for the Alk vastly easier that anything Ive found and I feel its reliable. I was thinking of getting the Hanna calcium tester but it got bad reviews, so Ive stuck with the Salifert kit.
20. comment for Excess Demand for Alkalinity in Saltwater Reef Tank - Solution
Glad to help man! I love making the videos that no one else seems to cover. Typically, though, they seem to be difficult subjects LOL. I have a feeling my Saltwater Chemistry videos are going to increase in the near future. -Cheers
Whats up CJ. Ive watched several of your videos - good stuff. You're correct - the reason the mag never dropped is because I auto dose. In fact, in the middle of the dkh fall, I actually boosted the MAG back up into the problem zone. That boosting kept the problem going, but it allowed me to discover the problem in the end.
Dosing Kalkwasser in the auto top off is a great, simple, way to maintain levels in a small tank or a tank that doesn't have a lot of coral in it. Kalk is a balanced supplement in that it gives the tank equal parts of Alk & Ca. The only way that you would get into an issue like this, where you have inflated MAG levels, is if the salt mix you are using to do water changes has higher levels of MAG than you tank uses.
Charting.... Soft and LPS corals are very forgiving when it comes to fluctuations in water parameters. From the looks of it, it appears that you have a handle on the levels. Keeping a log is good, but it really doesn't become necessary until you start keeping SPS because the parameters have to be kept tight. Not only that, but keeping a log lets you see trends in your tank. Had I not kept a log, its doubtful that I would have seen this issue.
Thanks for the question - happy to help. - Cheers
No problem @ all and really glad it helped you. It took me a long time to learn that lesson.
Oh man, thats one of my biggest gripes about testing = how fast the test kits go stale... I dont ever make it to the expiration as I typically test weekly, but I do notice that about two months after opening Hanna Reagent or Salifert kits they start to give off fluctuating results. So use it or loose it with testing kits LOL. Go get some man. I think they had a price drop on Amazon for the Salifert kits...
I hear ya, 915Mang, Magnesium is usually used really slowly. Last year though, I added some Mangroves in the sump and they seemed to suck up the magnesium. It was then that the consumption of Mag increased in the tank. Who knows, maybe back then is when this problem started to form...
I think you're starting to see the light now - very exciting isn't it. It wont be long before you start moving into SPS.
Hey Wil. In most cases, Magnesium is used very slowly in a saltwater tank. This is because the Magnesium is primarily used as a buffer that keeps calcium and carbonate from binding together and precipitating out of the tank. With that said, most people do not find a need to auto dose magnesium in their tanks. The amount of Magnesium that you will dose will depend on many factors, but the main factor will be how many total gallons of water you have. Here is a great little online calculator for figuring out how much to dose into your tank: http://reef.diesyst.com/chemcalc/chemcalc.html
For me, and why I auto dose Mag, was because I added Mangroves to the sump and they typically use a lot of Mag out of a tank.
So, while dosing magnesium once a month may be enough for some people, it may not be enough for you. At this point though, with your Mag level at 1450, you should not dose any Mag. Reduce the Mag level so that it gets down into the sweet spot between 1250-1350. Also, your calcium is hi as well. You hi magnesium most likely has saved you some precipitation issues with regards to your Hi calcium in this case. You should reduce your calcium as well to more normal levels of between 380-450. Here is a simple, silly, video I did on the roles of magnesium, calcium and carbonate in the reef tank: https://youtu.be/vLe4I6D1Sqk?list=PLy2ZwPZp7oyNtGvtVGHAQK_Dhm87Z-Txp
A final piece of advice here, one that is difficult for me, is to be patient when making additions or reductions. Pay attention to your alk levels and avoid rapid fluctuations in it.
Thanks for the question - happy to help. -Cheers
Hey thanks man. Really appreciate the vote of confidence. I wasn't sure if I should even make this video because its kinda complex and I wanted to be able to describe it as simply as possible for everyone. Surely tons of us Reefers have to learn this lesson the hard way, and I'm hoping this helps people as I didn't find anything on YouTube when I was looking into this. Thanks again - Happy Reefing :D