Alk newbie help

[Foxchase]

So over the last few weeks, I've noticed my dkh has been lower than it used to be. I use IO RC which when mixed is at 11dkh (hanna). Testing recently, I saw my tank dkh drop all the way down to 6.8. I do 25% WC once every 2 weeks. I also have an auto water change system set up to do about 3 gallons every 2 days. I don't have any sps only lps, softies and anemones.

The problem is, my calc is high and so is my mag.
What can I do to correct this? Here are my latest test results:

Temp: 78.6
SG: 1.025
Ph: 8.2
Am: 0
Nitrite: 0
Nitrate .25
Phosphate: .02
Alk: 6.8 before water change and 7.4 after WC yesterday
Calcium: 520
Mag: 1800

 

[Caseyoidae]

You can just dose alkalinity component of two part. ( soda ash) to bring it up. 7.4 is fine though. Natural sea water is 7. Calcium should fall on its own, not sure how mag is so high. Maybe try a different test? Lots of people don’t bother testing mag. No3, po4, alk and cal are the most important to me.depending on total system volume you may want to change less water. If everything looks happy I say keep doing what your doing!

 

[Foxchase]

You can just dose alkalinity component of two part. ( soda ash) to bring it up. 7.4 is fine though. Natural sea water is 7. Calcium should fall on its own, not sure how mag is so high. Maybe try a different test? Lots of people don’t bother testing mag. No3, po4, alk and cal are the most important to me.depending on total system volume you may want to change less water. If everything looks happy I say keep doing what your doing!

Only reason for the water change is to keep the alk levels stable as I've seen it drop to 6.5. Mag has always been high and so has calc. I've never seen them drop. Maybe a couple points here and there but not much

 

[Caseyoidae]

Oh, I’d pick up some bulk reef supply soda ash, mix it up in a gallon of ro water. Test, then test again in 24 hrs to figure out daily consumption of alk. Then use the brs dosing calculator or guess and check the dosing amount everyday until you get it dialed in. Everyones tank is different but I find this calculator to be a good starting point. https://www.bulkreefsupply.com/reef-calculator
There are also other options to raise alk on there.

 

[vetteguy53081]

@Randy Holmes-Farley

 

[Rybren]

You won't see much of a change in calcium or mag on a day by day basis. For every 2.8 dKH of alk consumed, you'd only have a drop of 18-20 ppm calcium, and 0-2 ppm magnesium.

My guess is that your Mag values are off due to test error. What test kit are you using?
Calcium is a tad high, but shouldn't cause any significant issues.

Water changes aren't the best way to maintain alk. As others have mentioned, dosing the alk portion of one of the many 2-part systems is a much better alternative and will reduce the fluctuations.

 

[Foxchase]

You won't see much of a change in calcium or mag on a day by day basis. For every 2.8 dKH of alk consumed, you'd only have a drop of 18-20 ppm calcium, and 0-2 ppm magnesium.

My guess is that your Mag values are off due to test error. What test kit are you using?
Calcium is a tad high, but shouldn't cause any significant issues.

Water changes aren't the best way to maintain alk. As others have mentioned, dosing the alk portion of one of the many 2-part systems is a much better alternative and will reduce the fluctuations.

I'm using Red Sea for calc and mag. Hanna for alk (checked with Red Sea to make sure it's accurate) I've double checked the mag and calc almost every time and I get almost the same result +/- for variation. The water has always tested that high for mag and calc. Alk also always tests at 11-12 (I test the freshly mixed saltwater before wc)

 

[Foxchase]

What should I be looking for to dose?

 

[Rybren]

A lot of people seem to have problems with the Red Sea mag test. I've never tried it - Salifert works great for me.

Not exactly sure what you mean by " What should I be looking for to dose? " Are you asking about a specific product or how to do it?

For a specific product, I'd just use the Alk portion from Randy's 2-part recipes.
As to how to do it, I'd measure the alk daily for a few days to get an idea of your average daily consumption and then use one of the calculators in the stickies to figure out how much to dose (or just go with trial and error)

I'd also consider switching to a different salt that more closely matches your target parameters.

 

[Foxchase]

A lot of people seem to have problems with the Red Sea mag test. I've never tried it - Salifert works great for me.

Not exactly sure what you mean by " What should I be looking for to dose? " Are you asking about a specific product or how to do it?

For a specific product, I'd just use the Alk portion from Randy's 2-part recipes.
As to how to do it, I'd measure the alk daily for a few days to get an idea of your average daily consumption and then use one of the calculators in the stickies to figure out how much to dose (or just go with trial and error)

I'd also consider switching to a different salt that more closely matches your target parameters.

Yes that's what I meant. What product. I'll look into it. As for salt, what do you mean more closely matches my parameters? Like how?

 

[Rybren]

Yes that's what I meant. What product. I'll look into it. As for salt, what do you mean more closely matches my parameters? Like how?

The salt mixes from each manufacturer have differing levels of alk, calcium, magnesium, etc. You can switch to one of the mixes that have amounts closer to your preferred levels. For example, if you want to keep your tank at an alk of 8.0, select a salt that mixes to that (or close to it). That way, when you're doing a water change there is less of an effect.

Somewhere here on R2R there is a thread tracking the levels of many different mixes. I'll see if I can find it.

Edit: I couldn't find the thread, but here's a link to a chart put together by a R2R member https://reefstable.com/blog/salt-mix/

 

[blasterman]

Alk is always depleted at a higher and often less predictable rate than calcium and magnesium. However, the reef industry has everybody brain washed that you need to constantly test and dose for all three even if you don't have stony corals. In a young tank alk might actually deplete faster than your water change can replenish. That's why salt mixes like reef crystals have higher default levels of alk. Reef Crystals right now might be a better option for you for than IO.

If you don't have lots of stony fast growing corals I wouldn't bother testing calcium....maybe once a month. Maybe not at all.

Bonus tip - if you aren't depleting calcium don't bother testing magnesium (or strontium) because calcium, magnesium and strontium are typically taken up by stony corals at a fairly relative rate.

My humble opinion is just switch to Reef Crystals.

 

[Foxchase]

Alk is always depleted at a higher and often less predictable rate than calcium and magnesium. However, the reef industry has everybody brain washed that you need to constantly test and dose for all three even if you don't have stony corals. In a young tank alk might actually deplete faster than your water change can replenish. That's why salt mixes like reef crystals have higher default levels of alk. Reef Crystals right now might be a better option for you for than IO.

If you don't have lots of stony fast growing corals I wouldn't bother testing calcium....maybe once a month. Maybe not at all.

Bonus tip - if you aren't depleting calcium don't bother testing magnesium (or strontium) because calcium, magnesium and strontium are typically taken up by stony corals at a fairly relative rate.

My humble opinion is just switch to Reef Crystals.

Sorry I shoulda been more clear, this IS with reef crystals. It's the only salt I've ever used