?? re: Alk/Hardness tests

[Jan]

Well,

I haven't tested my Alk in quite a while in spite of the fact that I add Reef Builder (calcium carbonate) to my top off water every day. My ph probe registers between 8.19 in the am and 8.40 in the pm every day. So I have been assuming that this okay ph reading indicates that my Alk must be okay too.

Anyway, once again I got strange Alk test results--the last time I tested the results were off too, leading me to think I needed new test kits besides API.

Tonight I used a Salifert Alk test kit that had been given to me. I don't know if it's expired or not but I tested twice and both times the blue liquid did not change color at all, even after adding 1.0 ml of reagent to the vial. Then I switched back to API. The API test required 16 drops to change color and the end of the scale they provided was only 12 drops. So I don't know my real reading but this seems way too high anyway.

Last I tried the el-cheapo 5-in-1 test strip (Mardel). This one gave me a hardness reading of 250 "very hard" and an Alk reading of over 300...again, off their chart. And could someone please explain the relationship between Alk, hardness, and ph? I thought they were all pretty much the same, that if your ph was high then your alk was high too. But my ph seems okay so I'm confused.

So this must be bad. Do I need to do something to decrease the Alk immediately, or can I just stop adding Reef Builder to my top off water for a while?


OK according to my Salifert Calcium test (not expired), my calcium is only 335. So it seems that my overly high Alk has caused the calcium to drop in spite of new Calc reactor.

Advice please?

 

[HarleyDude]

There have been a lot of reports of issues with the Salifert Alk test. I too had problems with one of my kits.

See this thread on RC http://www.reefcentral.com/forums/showthread.php?s=&threadid=1117617

 

[DonW]

Your blind dosing, which makes it impossible to get any Idea of where you may or may not be. I would use the salifert with only half the amount of water. In the mean time just get a new salifert test kit to verify with.

Don

 

[HarleyDude]

Do as Don stated and get another Alk test to make sure that your results are accurate (Alk off the chart). Also, make sure the Salifert lot #'s are different and the expiration date (yellow sticker on box) is the newest possible.

This is all on the assumption that your Alk is high -- please keep that in mind. Let's say your Alk is high, your Ca is low and your pH is where you want it. You most likely got here by adding buffer to get your pH where it is which in turn raised your Alk. Now, as stated before your Ca has dropped because the high Alk is precipitating calcium carbonate. Running a Ca Reactor at this point is not going to help, but hinder. It will move your Ca and Alk in parallel and again that is not accounting for the precipitating calcium carbonate. The only way to adjust this is to add a caclium chloride additive, like Kent Turbo Calcium or the Calcium portion of a 2-part additive (be sure to not add the Alk additive). While your Alk is still high, it will consume some of what you add. Also, stop using buffer (if you are) directly to the tank and your make up salt water. I would add buffer only to your straight RO water (for evap) to bring those parameters to meet your tank. This should eventually bring everything back in line.

 

[Jan]

OK

In addition to getting a new test kit....


I plan to do a 10% water change tonight then to retest with the kit I have now if I can't find another good one (anything besides API). I will dial back the calc reactor a lot to a slow drip only.

I refilled topoff bucket with regular, non-buffered RODI last night. (I haven't been dosing my tank or makeup SW, only my top-off water.)

I have Kent liquid calcium supp (calcium chloride) at home already and can add some after my water change. I will be back online after the water change and test, to confirm the correct amount of calcium chloride to add.

thankyou....

 

[roblou]

Jan: one thing you might try is to test your freshly made up water with the Alk test kits you have. Depending on what kind of salt you use, I'll bet you can find some numbers on this forum (or maybe RC) for typical Alk readings for various brands of salt. For instance, I use Reef Crystals, and freshly made up, it usually reads 11dKH Alk for me (at 1.026).

This might at least give you an idea if your test kits are giving you good readings.

hth,
rob

 

[HarleyDude]

A couple things - here is a link to a calculator that should help you determine how much Ca additive you will need to add. Keep in mind that precipitating calcium carbonate which will consume some and be sure to read what the calculator page says.

There are a few sites that have the initial parameters after different brands of sea salts are added. If you post what type of salt you use and don't know where these articles are, I will find out what the parameters are in these studies.

Not sure what the cross linking policy is here -- I should look that up.

 

[Jan]

thanks, Roblou and Harleydude.

I'm using Red Sea Pro Reef salt right now, just started a new bucket.

 

[HarleyDude]

I can not find any details on that salt from the studies. I know Eric Borneman and Kim Lowe's study is supposed to be released soon -- haven't seen details yet.

 

[Jan]

After 4 days of adding no Reef Builder (calcium carbonate) to my top-off water, and also adding 1 capful of calcium chloride, there has been no reduction at all in my dhk. It still reads ~16 on the API test kit. Calcium reads 370, up from 330 last test.

I'm about to start a 10% water change but I'm surprised that the Alk has not come down on it's own. I may need to adjust my calcium reactor somehow but not sure how to do that without dropping the calcium level as well.

Should I turn off the reactor's CO2 for a while until my alk is in the ~10 range, and then turn it back on again? Or any other advice other than the water change?

 

[HarleyDude]

At this point your Ca reactor isn't doing anything but hindering, so I would turn it off. Once your alk comes back, turn it on slowly until you find a balance. Keep dosing with Ca chloride.

 

[roblou]

Jan: I agree w/HarleyDude that you should shut off the Ca reactor now. After you do the water change, I would also suggest that you stop dosing everything for a few days. IME, it is much harder to figure out your tank's chemistry when there are too many inputs being added.

I would be much less concerned about Ca dropping vs Alk at 16dKH (btw, I suspect that reading is not the true dKH). But you really want to get both Alk & Ca back to balance before you start up your Ca reactor again.

Good luck & hth,
rob

 

[Jan]

OKay guys, thanks...

 

[Jan]

Update:

My alk has finally dropped to 12dhk after dialing down the Calc Reactor to practically nothing. It was at 14, then 14, then 13, now 12 (over 4 days). Last night I noticed some TN on one of my corals, half way up, in a "V" shape. No other TN on other corals, but could my ALk be dropping too rapidly or something, causing the TN? I was planning to let it get down to 9dhk and then try to keep it there. Does that sound healthy?

 

[roblou]

9dKH is what I target also, which is right in the middle of the recommended level for reef aquaria (7-11 dKH), and just slightly higher than typical NSW (7 dKH).

http://www.reefkeeping.com/issues/2004-05/rhf/index.php

Regarding the TN, I would think your high Alk levels would have caused that, not the slow dropping of it. IMO, if you're just letting the Alk drop naturally, that's about the best you can do to get it back to the proper level. Hopefully the TN is slow, and the coral will recover.

Good luck,
rob

 

[Jan]

It's weird, Rob, because during the time that my Alk was so high (up to 16dhk), my corals all looked good with lots of PE and the fastest rate of growth I've see to date. It seems strange that only now after the ALk has come down close to NSW levels that I see the TN. Not impossible but counter-intuitive to me.

 

[roblou]

Yes, I agree w/you it seems strange. I know this was discussed at the beginning of the thread, but thought I'd bring it up again: are you sure your Alk test is producing correct reading? I just hope that your original 16 dKH reading was not more like 9, and now your 9 reading is not really 2 or 3.

I think you said you bought a new test kit, but not sure. Are you still using the API test? I've heard those produce false high readings...

 

[Jan]

I got the original high results with a Salifert test (which would not change color). I repeated the test with API which showed ~16dhk. I have been repeating the API test because it's easier/faster to do. I haven't heard that API give inflated readings. You have, it seems? Are we talking about slightly inflated or grossly inflated readings?

 

[roblou]

I used to use API Alk and Ca test kits. I liked them because they were pretty easy to use. I've since switched to Salifert. The resolution on their tests are much better than API I think. I didn't have a chance to compare the 2 personally, so my comment is definitely hear-say.

But, previous 16dKH readings to me seem very strange...to have not had a negative effect on your livestock. I think that is way above the recommended safe levels, which leads me to believe that if your livestock was all happy when you were reading 16dKH, that it really wasn't that high.

IMO, it's worth a 2nd opinion by either taking in a sample of your water to LFS (or fellow reefer), or testing someone elses water with your test kit. Just hate to think you're taking the wrong action based on a false reading from your test kit...

hth,
rob

 

[DonW]

I would buy two of the same brand out of the same batch. Alternate their use as long as they are close to each other and you keep your parameters somewhere in middle between high and low youll be fine. The instability is going to cause more problems than anything else.

Don