alkalinity questions

[LCP136]

I just tested my water with an API test kit that gives you alkalinity in ppm. I read that to find dKH you divide by about 17.8, which gave me about 6.8 dKH, which is certainly low. That leads to my question, what is the best way to raise the hardness of my reef?

[LCP136]

Oh, this should probably be in the chemistry forum. I put it here because I'm trying to adjust my levels for my SPS.

[ange062]

Use a 2-part to get it back in line. Also check your Ca and Mg to see where they are. Low Alk likely means low Ca also. This is a good and easy to understand article:
http://www.advancedaquarist.com/2002/11/chemistry

[LCP136]

Thanks for the article.

[dzhuo]

I read that to find dKH you divide by about 17.8, which gave me about 6.8 dKH, which is certainly low.


6.8 dKH isn't really that low so don't take any drastic measure to raise it. Except Salifert, most alk test kits are designed for fresh water which measure about 10% lower.


That leads to my question, what is the best way to raise the hardness of my reef?

I would start with dripping kalk first to see if it's able to maintain your alk / cal. If not, then look into either 2-part or a cal reactor.

[ptr13]

+1 to two part,you will raise it in no time.

[LCP136]

My numbers are
calcium: 340 ppm
alkalinity 6.8dkh
magnesium: 1000 ppm

The numbers are terrible, but I would like to raise them a little bit. I think dosing magnesium as well as a two part will be my plan of attack.

[kaserpick]

You would certianly want your Mg level higher, if you're raising Ca+ and KH. Many times, when I think of 2-part, it feels like Mg gets over looked. But, without an elevated Mg level, Ca+ and KH will not stay in solution as long as they typically could/or should. In other words, you could dose Ca+ and KH additives accordingly and still not achieve the desired levels.

So, yes, dosing magnesium as well as 2-part would be a good 'plan of attack'. :)

How does your pH look?

[dzhuo]

My numbers are
calcium: 340 ppm
alkalinity 6.8dkh
magnesium: 1000 ppm


All of your params seem consistently low. I think there is a possibility these are either testing error or bad test kits. Are they always these low? How often do you test? What salt do you use? When is the last time you done a water change or adding 2-part or kalk? I can't imagine any popular salt (except maybe TMP) would yield such low params. Unless you have huge alk / cal demand and haven't dose anything in a while, it seems suspicious. Have you test a fresh mix to rule out a bad batch of salt?

[LCP136]

I've started testing since I've started getting seriously into SPS. Before this month I had a colony of acropora, a colony of montipora, but that was pretty much it for SPS, and they were doing fine. Recently, however, I've wanted to expand my SPS so I have started testing, and the numbers have been consistent. I do about a 10 gallon water change weekly on my 90 and I use Instant Ocean. My pH is good, about 8.2.

[JAustin]

Sounds like you need to start dosing 2 part like said before. Check out bulkreefsupply.com and get their two part starter kit with the gallon jugs....it will be enough to last you a year of more!

You may want to move to instant ocean reef crystals, that has higher levels of MG, CA, and Alk. When you do your water changes it won't lower your levels but raise them a little.

Good luck!

[LCP136]

I'll look into the reef crystals as well as a two part kit. Thank you everyone.

[Stanley-Reefer]

If your tank is looking good---don't get hung up on those #s either---if the kit is off you could be doing more harm than good. Make sure your sg is good too--if you don't mix to 1.025-26 you won't come close to the manufacturer's #s of CA/Alk/Mg

[dzhuo]

I do about a 10 gallon water change weekly on my 90 and I use Instant Ocean. My pH is good, about 8.2.

With a +40% monthly water change using IO and the current SPS you have, I believe your listed params are way off. Have you try testing a fresh mix to see what the params are? You are either:

1. Having a bad bucket of salt. Somewhat unusual given IO's consistency.
2. Your test kits are bad or there are testing errors.
3. Your salinity is way off. It's lower than what you think it's.

I wouldn't start dumping 2 parts into your tank since you will need a lot of it and without knowing a good ballpark where your params are, it would really do damage. Are your corals suffering? Or is there any indication your tank is low in alk / cal / mg?

[LCP136]

My specific gravity is 1.023. My test kits could be faulty. I am using API calcium/alkalinity tests. I always test twice and get the same result, but the kits could be testing consistently low.

[dzhuo]

My specific gravity is 1.023.

1.023 is a little low and I would try bring it up to 1.025 or 1.026 slowly with water change. Once there, try test a fresh mix to see what you get. I would also consider another brand of test kit such as Salifert. Once you confirm the readings, I would try to see if kalk is enough (given your current SPS and demand) but 2 part is a fine solution as well.

[LCP136]

How's Red Sea for testing?

[newbie916]

I like ELOS test kits..

What ever you do don't try to correct your parameters too fast. Alk swings will stress and kill sps. I'd definitely try a better reef salt and start doing a 2-parts dosing regiment to keep your parameters up.

I went from Reef Crystals to D&D H2Ocean salt and I no longer have to dose Mg. My Mg stays at 1500-1550. I still dose Alk and Ca, but the better salts will reduce the amount you need to dose.

[dzhuo]

How's Red Sea for testing?

I have no personal experience with Red Sea or API, I have always used Salifert for alk / cal / mg. My impression and from reading other's experience lead me to believe Salifert is most consistent.

[LCP136]

Instead of dropping 65 dollars on new test kits, I think I'm going to go into the LFS and have them test the cal/alk/mg. If they're using a different kit and get different numbers I'll look into new kits. I think they might use salifert anyhow.

[dzhuo]

Sounds like a good plan. Good luck!