PH, Alkalinity, and Calcium

[jaws789832]

I have a 120 mixed reef, lightly stocked atm, but trying to slowly build up to a stocked mixed reef so trying to dial things in and get a better understanding of things. Up until about 3 weeks ago I was keeping everything in check by maintenance and regular water changes but wanted to experiment with 2 part dosing. All my parameters are very good.
0 nitrates and 0 phosphates, but I know I have some because I do have some algae growth in the sump and on the glass so I am pretty sure they are about where they need to be. Plus I do feed the 5 fish I have pretty heavy because I enjoy seeing them fat and happy.

Before I started dosing my alk was about 8 after a water change and about 7.3 just before my 2 week water change, so it was dropping as expected.

My calcium on the other hand would do just the opposite as expected. It would be about 370 after a water change and raise to about 400 after, using the salifert test kit. I thought maybe the tesk kit was wrong so I purchased the hanna checker and even though the numbers were way different the same trend was happening. With the hanna I am getting 460 after a water change and it rises to 490 before a water change. The numbers are drastically off but the rise (when one would think it should drop) is the same. I also have the salifert strontium test kit which has a built in calcium test and its numbers actually mirror the hanna checker 460-490, so I am inclined to believe those numbers.

My PH (using and apex probe) was swinging from 8 to 8.3 day night and day. probe was calibrated before I started doing all these tests about 2 months ago.

About 10 days ago I started attempting to dose. Step 1 was going to be to get my alk up to 9dkh and keep it steady. I wanted to do this very slowly with no drastic changes. I am using the BRS 2 part and only dosing the soda ash at a rate of 24ml over a 12 hour period at night. I have added extra (more than the 24) at times but always watching my ph closely in order to get to the 9 (probably slower than necessary) Right now I am at 8.5

My thought was if I get the alk up, My calcium should be used up more and things should stabilize to the point I would have to start dosing the calcium part of the 2 part.

my 2 questions are,
1. since I started dosing the soda ash, my PH has gone up (which I was expecting a temporary jump but I am a little worried now). It is hovering in between 8.2 at night and jumping up to 8.4 during the day, with a couple of peaks in the 8.43 range. 8.4 is getting a little out of my comfort range. Is there anything I should be doing to keep the PH lower? Should I be dosing the calcium anyways during the day? would that help with the PH swings?

2. My calcium is still raising at the same rate. 460-490 over these last 10 days since I started dosing the alk. Is this normal and possible? or is it testing error? Should I still dose the calcium part even if the tests show I dong need it?

My tank is doing great. The corals are growing with good color, Birdsnest, monti's and stylphora's(sp) are growing. Hammer, torch, chalice, acan, Duncan, all pretty and appear happy and healthy. Fish are all doing fantastic. Only problem I have had is I bought a urchin (impulse buy) a week ago and he has lost all his spines after 2 day in the tank (so I assume that isn't good) but I chalk that up to me doing something wrong and taking the advice of LFS.

You might ask why am I dosing in the first place if I am able to maintain fine without it, or say stop chasing numbers if everything is going well. I am just trying to understand the process so when dosing does become necessary in the future its not a mystery and I have the confidence and experience to do it. I don't chase numbers but I do enjoy testing. For me that's part of the fun of this hobby and helps me learn the ins and outs of what is really happening inside the tank.
anyways thanks in advance for helping me expand my knowledge.

 

[Randy Holmes-Farley Verified Community Expert]

I'm not sure why you saw calcium rising between water changes, but that isn't normal and may be test error if you added none. Are you using tap water?

The increase in the rate of consumption of calcium between an alk of 7 dKH and an alk of 9 dKH will be real, but not always easily detected except in the long run. You will also need to dose a correspondingly larger amount of alkalinity to maintain an alk of 9 dKH compared to an alk of 7 dKH, for the same reason: increased consumption.

Your pH swings and pH values are just fine. There's no need to worry about high pH until it starts getting above 8.55 or so, and even then the primary issue is jsut increased precipitation of calcium carbonate on pumps and heaters.

 

[Sabellafella]

I have a 120 mixed reef, lightly stocked atm, but trying to slowly build up to a stocked mixed reef so trying to dial things in and get a better understanding of things. Up until about 3 weeks ago I was keeping everything in check by maintenance and regular water changes but wanted to experiment with 2 part dosing. All my parameters are very good.
0 nitrates and 0 phosphates, but I know I have some because I do have some algae growth in the sump and on the glass so I am pretty sure they are about where they need to be. Plus I do feed the 5 fish I have pretty heavy because I enjoy seeing them fat and happy.

Before I started dosing my alk was about 8 after a water change and about 7.3 just before my 2 week water change, so it was dropping as expected.

My calcium on the other hand would do just the opposite as expected. It would be about 370 after a water change and raise to about 400 after, using the salifert test kit. I thought maybe the tesk kit was wrong so I purchased the hanna checker and even though the numbers were way different the same trend was happening. With the hanna I am getting 460 after a water change and it rises to 490 before a water change. The numbers are drastically off but the rise (when one would think it should drop) is the same. I also have the salifert strontium test kit which has a built in calcium test and its numbers actually mirror the hanna checker 460-490, so I am inclined to believe those numbers.

My PH (using and apex probe) was swinging from 8 to 8.3 day night and day. probe was calibrated before I started doing all these tests about 2 months ago.

About 10 days ago I started attempting to dose. Step 1 was going to be to get my alk up to 9dkh and keep it steady. I wanted to do this very slowly with no drastic changes. I am using the BRS 2 part and only dosing the soda ash at a rate of 24ml over a 12 hour period at night. I have added extra (more than the 24) at times but always watching my ph closely in order to get to the 9 (probably slower than necessary) Right now I am at 8.5

My thought was if I get the alk up, My calcium should be used up more and things should stabilize to the point I would have to start dosing the calcium part of the 2 part.

my 2 questions are,
1. since I started dosing the soda ash, my PH has gone up (which I was expecting a temporary jump but I am a little worried now). It is hovering in between 8.2 at night and jumping up to 8.4 during the day, with a couple of peaks in the 8.43 range. 8.4 is getting a little out of my comfort range. Is there anything I should be doing to keep the PH lower? Should I be dosing the calcium anyways during the day? would that help with the PH swings?

2. My calcium is still raising at the same rate. 460-490 over these last 10 days since I started dosing the alk. Is this normal and possible? or is it testing error? Should I still dose the calcium part even if the tests show I dong need it?

My tank is doing great. The corals are growing with good color, Birdsnest, monti's and stylphora's(sp) are growing. Hammer, torch, chalice, acan, Duncan, all pretty and appear happy and healthy. Fish are all doing fantastic. Only problem I have had is I bought a urchin (impulse buy) a week ago and he has lost all his spines after 2 day in the tank (so I assume that isn't good) but I chalk that up to me doing something wrong and taking the advice of LFS.

You might ask why am I dosing in the first place if I am able to maintain fine without it, or say stop chasing numbers if everything is going well. I am just trying to understand the process so when dosing does become necessary in the future its not a mystery and I have the confidence and experience to do it. I don't chase numbers but I do enjoy testing. For me that's part of the fun of this hobby and helps me learn the ins and outs of what is really happening inside the tank.
anyways thanks in advance for helping me expand my knowledge.

If your calcium raised before ur next waterchange id look into testing mag to see if it does the same. If so, your sg is moving up.

 

[jaws789832]

Thanks a bunch for the quick replies. Its reassuring about the PH because that was my biggest worry. The amount dosed is already happening. That original 24ml isn't even able to maintain the 8.5 dkh without me dosing a little more manually. I am going to up my dose but I wanted to do everything real slow so I didn't have any major swings or more importantly major screw ups on my part LOL. heheheh that's part of the confidence thing.

As far as mag, I didn't check it this morning but 3 days ago it was at 1350 and pretty much (with the water changes always remains there. I use IO reef crystals salt atm but if I get all this dialed in was going to switch to regular IO.
Sg is at 34.5. I maintain it at 35, but through the course between water changes it drops slightly due to ATO, skimmer cleanings, removing a little water testing, and just water dripping from feedings and putting my hands in the tank it usually drops a little. I use the Apex probe for salinity, with the occasional refractometer (about once a week) to verify. The probe is calibrated about once every 3 months (with the correct solution) but the refractometer is calibrated before every use using DI water (which I know isn't the best but my readings seem to match). I do use only RODI water in the tank with 0 TDS but my regular tap water is extremely hard (calcium deposites on all my faucets). Even though I have 0 tds can some calcium leach through and be in my water? I have never tested my fresh saltwater to see what that is running or my RODI to see if any calcium was present. My TDS meter is just the inline one from the BRS RODI unit.

 

[Randy Holmes-Farley Verified Community Expert]

There's should not be enough calcium in the 0 ppm TDs water to boost calcium in the tank.

If the salinity went from 34.5 to 35 ppt, that would boost calcium by about 6 ppm.