Aquarium Chemistry Question? Ask the Doctor!

Randy Holmes-Farley · Sep 7, 2017

You're welcome.

Happy Reefing.

bif24701 · Sep 19, 2017

Sdot said:
Follow-up question. Will feeding them directly not suffice? Also i thought with me dosing the tank that would raise the PH? What could i do naturally to raise it, dose kalkwasser?

Not so in my experience. I just noticed a few acros started to pale in the last few days and did water tests. Found my NO3 was .50ppm. That's not good for my system because I have lots of light, flow, and higher ALK (10dKH) so things just do better when there is ~5ppm NO3. My system is clean, though I feed very heavy, so keeping NO3 at that mark is difficult. I dose PNO3 (stump remover) when it gets low and bring it to about 5-10ppm. I've also had to add some Seachem phosphorus when PO4 was undetectable with my Hanna ULR Checker and stayed there for some time. I have cut back on water changes and removed filter socks and that's helped. What almost certainly has not was feeding more or directly feeding coral foods. I did observe strong growth spurts but colors would still quickly fade if NO3 dropped too low.

By the looks of it your system is very clean and/or new and you certainly need at least a small amount of both NO3 (>1ppm) and PO4 (~.03ppm). I would get each of these taken care of because it can/will lead to problems, possibly RTN/STN.

ivans · Nov 1, 2017

Recently I had a reef transfer from small tank to bigger one. During this transition period I was adjusting my new calcium reactor and got KH about 6.0. All this had taken more than one month until l have reached KH 8-9. All that time I didn’t measure the Ca level.
Two weeks ago I got my test results from Triton labs. Ca was about 300.
My question is: what could be the reason of such disbalance?
Thank you.

Randy Holmes-Farley · Nov 1, 2017

ivans said:
Recently I had a reef transfer from small tank to bigger one. During this transition period I was adjusting my new calcium reactor and got KH about 6.0. All this had taken more than one month until l have reached KH 8-9. All that time I didn’t measure the Ca level.
Two weeks ago I got my test results from Triton labs. Ca was about 300.
My question is: what could be the reason of such disbalance?
Thank you.

I do not know. There's not really any way that calcium is consumed and alkalinity is not, but if you were somehow dosing alkalinity and not calcium, then that could explain it. The reactor could do that with excessive dolomite or other magnesium heavy media, but it might be testing error, or other sorts of alk additions or a mix for water changes that was off.

ivans · Nov 1, 2017

Thank you Randy. I’ve never thought about such possibility with CR and magnesium media. Actually I added some KZ magnesium media to my reactor with Korallin media. As it’s my first experience with calcium reactor I’m ready to agree with my fault. But the magnesium level hasn’t changed significantly- from 1375 to 1390.
I refuse the testing errors because my Salifert showed the same.
For the described period of time I didn’t change water and didn’t add any additions.

Randy Holmes-Farley · Nov 1, 2017

ivans said:
Thank you Randy. I’ve never thought about such possibility with CR and magnesium media. Actually I added some KZ magnesium media to my reactor with Korallin media. As it’s my first experience with calcium reactor I’m ready to agree with my fault. But the magnesium level hasn’t changed significantly- from 1375 to 1390.
I refuse the testing errors because my Salifert showed the same.
For the described period of time I didn’t change water and didn’t add any additions.

I don't know if that magnesium rise is accurate, but if it is, and alk was stable, calcium would decline by 25 ppm.

ivans · Nov 2, 2017

May be. But what is the reason of others 100 ppm of Ca decline?

Randy Holmes-Farley · Nov 2, 2017

ivans said:
May be. But what is the reason of others 100 ppm of Ca decline?

The only possibilities are water changes with a mix that has inadequate calcium, or additions of alkalinity that you are not accounting for. Top off water, buffers, the reactor dolomite, dosing of nitrate, etc.

ivans · Nov 2, 2017

Thank you Randy for sharing your thoughts. Only one thing coincides- magnesium addition to my CR. I see no other reason from above mentioned. You should be right.

Randy Holmes-Farley · Nov 2, 2017

You're welcome.

let' us know if you figure it out.

ivans · Nov 3, 2017

For sure, Randy, I'll inform you, if find a reason.

What I would like to know is if the measured KH figures correctly show the content of carbonates in the water (like for instance Ca or Mg in ppm)? Or it is rather relative indicator (like pH)?

Is it possible the next? Ca and carbs dropped down and stayed at that very low level for some time during my CR (calcium reactor) adjustment (KH was near 6.0). Step-by-step I have increased the KH level only by CR up to 8.0-9.0. During theses adjustments and some time after I didn't measured Ca. But in reality the Ca and carbs level didn't reach the required content.

I hope that I've managed to explain what I mean.

Randy Holmes-Farley · Nov 3, 2017

Alkalinity (in dKH or meq/L) is a measure of a variety of things, but mostly is bicarbonate plus twice the carbonate.

Diazcm · Nov 7, 2017

Hi Randy, Do you have a thread on two-part dosing? I'm having a small issue i'd like to clear up. I'm currently using Brightwell aquatics Reef code A & B for my Reefer 450 and i'm dosing equal amounts of 10mL/ day. Now my ALK has been rock solid at 8.1 DKH for 5 days straight and Cal has been creeping up 5ppm a day, currently at 445ppm ( i wanna be at 435ppm) My questions would be....
Do i stop dosing Cal and continue dosing again when it reaches 430-435?
if holding on Cal and continue dosing ALK would that unequal dose harm the system?
I know dosing needs to be equal but would dosing more or less of the other be a big deal down the road? ( ex: 10ml of cal and 5ml of ALK)

Current Parameters:
Cal- 445ppm (Red sea)
ALK- 8.1 (Hanna)
Mag- 1460 (Red sea) High for my taste
Phos_ 0.06 (Hanna ULR)
Nit- .050 (Red sea)

Scott.h · Nov 8, 2017

@Randy Holmes-Farley I was wondering about some things chemically concerning kalk. I'm dosing vinegar satuated with seachems kalk. It's really a 3 fold question.

First, It appears that seachem kalk (according to their site) is not the same as pickling lime, as they claim it doesn't effect alk. Why?

Second, I'm (newly) dosing enough vinegar (52 ml per day of seachem kalk saturated vinegar treating 100 gallons of water) to keep nitrates in check. It seems to be holding my alk steady despite their claim of it not adding alk. Why? My only reasoning behind adding kalk to the vinegar is to keep ph elevated while adding that volume of vinegar. I was planning on dosing 3 part as needed to maintain whatever needs adjusted from there.

Thirdly, I'm not doing water changes, so I was wondering what could potentially build up with impurities of their kalk, or if you think there is enough impurities for me to change my game plan now before a buildup could occur? Maybe I'll remove the kalk from the vinegar and see where my ph ends up. What's your take? Thanks

zeeGGee · Nov 10, 2017

@Randy Holmes-Farley Hi. Whats the preferred ratio of mag chloride - mag sulfate to supplement magnesium? Thank you so much.

Randy Holmes-Farley · Nov 11, 2017

Diazcm said:
Hi Randy, Do you have a thread on two-part dosing? I'm having a small issue i'd like to clear up. I'm currently using Brightwell aquatics Reef code A & B for my Reefer 450 and i'm dosing equal amounts of 10mL/ day. Now my ALK has been rock solid at 8.1 DKH for 5 days straight and Cal has been creeping up 5ppm a day, currently at 445ppm ( i wanna be at 435ppm) My questions would be....
Do i stop dosing Cal and continue dosing again when it reaches 430-435?
if holding on Cal and continue dosing ALK would that unequal dose harm the system?
I know dosing needs to be equal but would dosing more or less of the other be a big deal down the road? ( ex: 10ml of cal and 5ml of ALK)

Current Parameters:
Cal- 445ppm (Red sea)
ALK- 8.1 (Hanna)
Mag- 1460 (Red sea) High for my taste
Phos_ 0.06 (Hanna ULR)
Nit- .050 (Red sea)

It is fine to back off on one of the parts of a two part if you have a clear trend (well above testing noise) that suggests it is needed. Dosing pumps can be mismatched, the mix may not be exactly balanced, water changes mess with demand ratios, etc.

I discuss two part recipes and dosing here:

An Improved Do-it-Yourself Two-Part Calcium and Alkalinity Supplement System by Randy Holmes-Farley - Reefkeeping.com
http://reefkeeping.com/issues/2006-02/rhf/index.php

Randy Holmes-Farley · Nov 11, 2017

zeeGGee said:
@Randy Holmes-Farley Hi. Whats the preferred ratio of mag chloride - mag sulfate to supplement magnesium? Thank you so much.

It depends on whether this is part of a DIY two part system using calcium chloride (in which case you are already adding a lot of chloride so you use less of that form: 5 parts magnesium chloride to 3 parts magnesium sulfate) or a stand alone magnesium supplement used with others methods (such as limewater/kalkwasser, and CaCO3/CO2 reactor, or no real dosing of calcium at all). In the latter case, use 10 parts magnesium chloride to 1 part magnesium sulfate.