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low KH, Ca, Mg in fresh reef crystals


grafxalien

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I have been having issues with low KH, Ca, Mg which didnt make much sense to me since I do frequent water changes and have a low coral load. Anyways, have been slowly fixing that issue with Two part and Mg which has made the tank look better.

 

Anyways, before my water change today I decided I should check the levels in my fresh water.

Turns out to be SG 1.026 pH 8.4 KH 5.1 Ca 370 Mg 1080. Ph was API, the rest salifert.

 

I mix my water changes with RO/DI water with my own spectrapure filter; 0TDS on meter. I mix it in a 5 gal bucket with an AC70 powerhead overnight. No heater, but the powerhead makes enough heat to match temps. I put the lid on overnight to prevent things from falling in.

 

This was a fresh bag of reef crystals that I just opened. I bought a box of 4 bags around a year ago and this is the last bag.

 

Any ideas? Think this is bad salt or is my mixing technique wrong? Could leaving the lid on alter the CO2 available for mixing?

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Air contact stabilizes the pH but that's about it. Your low Mg and Ca are just the salt. You probably got a bum batch. Have you tried any other salt? Red Sea Pro is the favorite in my area.

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Those are instant ocean numbers not reef crystal numbers. I'd open another bag and test that mix. I would return it, if that is the case. Sorry for the troubles.

 

I use reef crystals and get consistent results.

Is the salt clumpy or solid in large chunks before you mix?

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It is either precipitation from improperly mixing (unlikely since this is the only bag you had the problem with) or the particles within the bag aren't mixed homogeously and stuff is settled out to the bottom. If it is really hard and clumpy, return it and get a new bag - if you have to break up chunks you should return it or throw it away if it was your fault. It's not all that expensive to not take chances with a bad batch.

 

When you get chunks like that from moisture, evaporation, then recrystallization - the particle sizes will not be homogenous and you will NEVER get it to mix properly and every single batch you mix from the bag (unless you use the whole bag) will be wildly different. Additionally, since there is so little water causing the clumping, you may end up with calcium carbonate which will permanently lower the ability to mix to proper Alk and Ca.

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thanks for the help. I have another batch mixing up tonight and I am going to test it tomorrow. This big was almost solid before I opened it. I am guessing that is the problem then. Doubt I will be able to return it since I bought the box around a year ago. What would cause an un-opened bag to go bad like that?

 

Anyways. Looks like running to the store tomorrow to get a new bag will be the solution.

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I had this problem using reef crystals when the bag was clumped together. I see the calcium precipitate in the bottom of the trash can.. I've got a few bags sitting in the garage that are unusable. I too wonder how it happens as I don't see any salt leaking out of them, but they must not be completely air tight so moisture gets in.

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bought a new bag yesterday. it was soft and free flowing. Mixed it overnight. SG 1.025 kH 8.3 Ca 360. The bag on the side says at 1.023 its supposed to have 405 Ca.

 

These are new salifert kits and I also just tested the kH standard solution that comes with the kit and it was spot on.

 

Am I mixing it wrong somehow? Could it be that since I make small batches (~3gallons at a time) that it is just not uniform?

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bought a new bag yesterday. it was soft and free flowing. Mixed it overnight. SG 1.025 kH 8.3 Ca 360. The bag on the side says at 1.023 its supposed to have 405 Ca.

 

These are new salifert kits and I also just tested the kH standard solution that comes with the kit and it was spot on.

 

Am I mixing it wrong somehow? Could it be that since I make small batches (~3gallons at a time) that it is just not uniform?

Are you slowly mixing the salt into RODI water? If you put the salt in before the water you will get all kinds of precipitation problems which cause Alk and Ca to be lower than they should be. I normally take 15-20 seconds to pour a cup of salt into RODI while mixing with the other hand.

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