How can you lower Mg?

porpoiseaquatics

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So for several weeks now, I've been chasing an unidentified problem in my DT. Some easy to have corals have died off (Hollywood Stunner, Birdsnest) while a couple of others have bleached out (my purple/green hammerhead is now neon green and white). What's most odd is that my purple/green frogspawn is unaffected. Same goes for most all of my zoa colonies. There's one that's not doing so hot. My other chalices are fine, my rastas are good, my acans are all fine. Acros are growing. Everything else has the right coloration.

Params:

pH: 8.2
Ammonia, Nitrite, Nirtrates: 0
Alk: 5 (I know this seems just a tad high)
Ca: 380 (this is a tad low)
Mg: 1600

I've been doing week water changes to try and get the params back to where they should be. For whatever reason, I decided to check my change water....Alk 4, Ca 400, Mg 1600. I thought WTH? Why is Mg so high in my change water? I don't know. I use Kent Marine basic salt. So no wonder I can't get my Mg to come down.

How does one safely reduce Mg without affecting everything else?
 
I have never heard anything good about kent. IMO, 1600 and 11 will not cause any issues. Mojo had issues with kent several years ago. Things won't change overnight, so pick a new brand and stick with it...hopefully after a few weeks you'll have some better results. Good luck!
 
Your alk is too high, more so than your mag.....IMHO...even though both are high....

get some salinity....never looked back.....and I just don't think every single Seachem product is great, actually some kinda suck....Salinity I think is the best thing they make...plus some staples that everyone should have like prime, stability, metro & focus.....
 
Are you are dosing something to increase Mg and Alk? I doubt the Mg is really that high if not. Have you verified that your test kit is accurate? I would have someone else test for you first before doing drastic measures.
I seem to remember seeing you post for help getting your Ca reactor online. Have you done that? That can spike your Alk at first until the reactor is settled in. Every time I change my Ca reactor media I go through an Alk spike.
 
porpoiseaquatics;903840 wrote: Good point Seth....yes put the CA reactor online just over a week ago.

Raise your ca reactor pH sepoint. This will have the effect of lowering the amount of media you dissolve and lower the alkalinity, calcium and magnesium you add tot he system. I'd do that before you switch salt brands.

You can turn the reactor off until your levels drop naturally through use by the system, then restart it at a higher setpoint. Takes time to dial one in. Test every couple days until levels get to where you want them, then restart the reactor, and monitor the levels (alkalinity mainly), raising or lowering the reactor setpoint as needed until you have stability in your levels. Test at the same time each day to ensure consistency.
 
porpoiseaquatics;903840 wrote: Good point Seth....yes put the CA reactor online just over a week ago.

That wouldn't affect the freshly mixed sw, though. Only tank water.

Like Lee said, kent is junk. You'd be better served with io or rc, although I really like seachem marine salt, especially if you have a good reactor.

Salt is too cheap to mess around with.
 
Hey Jeff change that salt bro! Kent is horrible. For what it is worth I've had nothing but good luck with Reef Crystals. I've tried almost all salts including Salinity. I have since been using Reef Cyrstals for the last two years.
 
I'd change salt brands just because Kent is terrible. I've used Seachem Reef salt for 3 years now without any issues. I believe its the same as Salinity.
 
knowing that there is a reactor online...raise your ca a bit...you're imbalanced right now. With alk that high, you should be around 440 ca, esp if your mg is at 1600. As Dave said, you can lower pH for your reactor, which btw, what is that set to? You tank "should" start to balance out over a few weeks, but again, Kent salt....imo, is no good.
 
It would probably be beneficial if I had a better understanding of how a CA Reactor works. Currently I have the first chamber set for between 7.1 and 6.5 (CO2 on and off). I can't say what my pH output is because my 2nd probe went bad and I've not had a chance to replace it yet.

Mg has dropped to 1480. CA is still 380. Here's what stinks ... By my Red Sea Pro kit, KH is 14 dkh, by my Sera kit it's 10 dkh. To me, that's a large discrepancy. The problem is, I could use 4 kits and they'd all probably be different. So where does one stop and what do you believe?
 
What type of media are you using? And is it large or small? Large media can take lower pH but the small stuff will turn into sludge and you'll have a mess on your hands. 6.5 is low for the small grain stuff....I want to say I ran mine around 6.8-7 The large media I ran at 6.5. You really don't need to concern yourself too much with pH coming out, just the 1st chamber. Do you have a dual chamber setup? If it's just 1, you can setup a little drip cup for the effluent to drop into before it goes into your tank so it'll raise the pH a little before getting into the system...that will help if you have low pH issues. Dual chambers typically don't have that issue beacuse the 2nd chamber acts as that buffer area to help raise pH before going into the system. Reactors are tricky to dial in at first....the drip rate as well as bubble count and pH all have effects on how much you're adding to your system. When dialed in though, they are fantastic! And it will take a few weeks to get it correct. Adjust little bits and test every 24-48 hrs to ensure your change is shown in the tank....and less time and you have off readings. Since they dose equal parts into your tank, make sure you have your levels accurate, or they will go off scale. Never use a reactor to raise your levels, thats just a headache and can throw things off once it's running.
 
Jeff,
Given what you have just posted, I would do a few things if I had the same situation.

Salt: I have read good things about Red Sea Salt on Reef Central. It is used a lot in other areas of the country. Can't comment on it personally, but I think it is held as a higher quality salt than say, Instant Ocean, which is what I use. Go to other areas of the country and and folks aren't familiar with Salinity either. I don't think a KH of 14 in new saltwater is that big a deal either. We all know that KH is one of the highest fluctuating levels we test for, and if it is 14 new, it will drop soon enough when it hits your tank.

I think your issue lies with your calcium reactor being new and not being dialed in. Make a choice in your salt brand, stick with that, and then you adjust your reactor to the particular chemical characteristics of the salt/DT system.

Reactor: narrow your RKL reactor hysteresis setting to the narrowest band there is. You pick a pH setpoint, then set .01 units as the hysteresis, so your current setpoint is 6.8, so your CO2 will turn on at 6.9 and go off at 6.7. A narrower hysteresis will give more control over the output of the reactor effluent.

I have found it is easier to set a drip rate and a bubble count and stay with that, and only adjust the reactor setpoint. About 1 bubble CO2 per second and about 60 ml/minute effluent rate is a good starting point. Doesn't need to be exact, just cloes to those points.

Assuming you have a consistent CO2 bubble rate and effluent rate, the relationship between reactor setpoint and KH (bicarbonates)/Calcium/magnesium released from reactor is inversely related. The lower you set the reactor pH setpoint, the more media you dissolve and the more KH/Ca/Mag will be released (more carbonic acid formed from the CO2 to dissolve the media). The higher the reactor setpoint, the less KH/CA/Mag released (less carbonic acid formed from the CO2 to dissolve the media).

IIRC, you are not heavy into SPS or other high calcium consuming animals, so I don't believe a second media chamber is really necessary for your setup. The net effect of the second chamber is it will add some extra alkalinity/calcium and mag to your system as the low pH effluent from the first chamber runs through it. If you remove it you may find you need to adjust your reactor setpoint down a bit, say from current 6.8 to 6.7 or similar. A single chamber would give more control over the effluent and how much media you are dissolving. Don't worry about pH in your system, not really important, as long as it is between 7.8 and 8.4.

Test Kit: go buy a Salifert KH test kit, and stop worrying about variances between different brands. Salifert is a great kit, IMO, and they give you a reference solution to test against. Pure Reef sells Salifert, around $20 I think for the KH test kit.

What I would do:
1. pick a salt brand and stick with it.
2. manually adjust your calcium to 450.
3. go get a Salifert KH test kit.
4. Change your RKE controller setpoint to the narrowest hysteresis allowed.
5. remove the second chamber from the reactor setup, then wait two days to test for KH with the Salifert test kit.
6. set bubble count and effluent rate to the above suggested rates and keep them there without playing with them.
7. Test System (tank water, not reactor effluent water) KH daily at about the same time. Based on readings, aim for a KH of about 9. If your KH is higher than that, reset the ca reactor setpoint (midpoint) up by .01 units of pH, like from 6.8 to 6.9. If KH is lower than 9, lower the reactor setpoint by .01 units of pH, like from 6.8 to 6.7. Wait 24 hours and repeat KH test and adjust again if needed. Do this until your reactor maintains system KH at your required level. Remember, lower reactor pH setpoint=more CO2=more media dissolved=higher system KH, and higher reactor pH setpoint=less CO2=less media dissolved=lower system KH.
 
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