SkylineView
New Member
- Joined
- Oct 30, 2022
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- Location
- Houston
- What state or country do you live in
- Texas
Hello my experienced reef friends. I have a 75 gallon mixed reef system. While the tank has been alive for four years, I’ve really rededicated myself to making it a healthy thriving environment for the last ~9 months. I’m struggling to have faith in any salinity checker and would appreciate some guidance from others about their tools or general process/principles for tracking this aspect of reef management.
Summarizing my experience to date. I bought a cheap Orapxi salinity checker when I got the tank, and measured it weekly with water changes etc. I was naive and didn’t know these things need calibration (my bad).
9 months ago, when I redoubled my maintenance and “tank improvement” efforts, I sent off an ICP. Orapxi said 35, ICP said 31.5. Not good, need to recalibrate.
After some research, I purchased a refractometer (brand Autoutlet). I was/am aware they also need calibration and did/do so regularly with both rodi (make sure it reads zero) and a calibration fluid (35ppt). I start with the rodi, set that to zero, then use the calibration fluid and set that to 35… then measure whatever I’m measuring for the week. I also let the refractometer acclimate to roughly water temperature (I’m in Houston, so my water change water can be 90 degrees). This seemed to work better and I had a few ICP tests that were all in line. Great.
My most recent ICP says the tank is back down to 32ppt. The refractometer says today (and at the same time I took the ICP a week ago)… 35ppt. The Orapxi, which I hold on to reasons I can’t explain, says 32. So… break out a new vial of the calibration fluid. The refractometer says 35. The Orapxi, in true form, says 44. :-)
Out of the options… I trust the ICP. I do not trust any of the tools I have (Orapxi, refractometer, and/or the calibration fluid). I really just want a process to measure salinity that will allow me to remove it from the uncertainty/concern bucket… so that I can move on to other ICP issues (high Aluminum, moderate phosphate, and a wild dearth of trace elements caused by my refugium).
I appreciate your time, experience, and opinions. Additional detail provided below in case it is helpful.
Other common questions:
How does the reef look? Looks the best it ever has, except for one hammer I clipped with my knuckle a week ago… and that refuses to forgive me. Fish are normal. Coral color is good. Coral extension is good. I have some gha that is driven by elevated nutrient levels, and I’m working on that (nitrate 19, phosphate 0.13). The gha is still in check.
What equipment do you have? Red Sea skimmer/lights/ato/reefmat. Phytotank (refugium in a bottle). I’m running a bit of gfo (1/3 cup), mixed with 2/3 cup carbon.
Is it possible you under filled the tank with saltwater and topped up a lot with ATO water instead after the water change? Possible, for sure, but I don’t think it happened this time. I checked the ato log (I use the Red Sea ato+), and it shows normal consumption on that day. Also, I took the ICP sample and did my own refractometer test at the same time… so they should have both been low if that happened.
What is your water change process? Mix 35 gallons of rodi in a trash can in the backyard, add Red Sea salt (blue bucket), and let it run for a day with a small power head and a sicce 2.0 with no hoses attached (just blasting water around). Once I’ve tested it with the refractometer and dialed it in with fresh rodi (and more testing) and let that mix, I run it through a sediment filter and add it to the tank. I change about 10 gallons a week. Later in the maintenance process I check the salinity in the DT to make sure it’s not out of whack.
Full weekly testing suite… but these are all the ICP result values:
Salinity ICP says 32.
PH 7.8
Nitrate 19
Phosphate 0.13 (this is the ICP number, and could reasonably be the subject of a companion post. My Hanna checker is my fifth test kit for phosphate, says 0.18, and api and Fritz both say as they have since day one, 0.50).
ALK: 7.3
Calcium: 395
Magnesium: 1314
Iodine: 0.07 (salifert said < 0.01)
ICP also indicated very low trace elements across the board, except for Aluminum which is very high. I presume it’s from my gfo (h33 bayoxide) and I may not have rinsed it enough. Unclear.
Livestock:
Fox face rabbit fish
Generic clown fish x2
Royal gamma
Flame hawk fish
Yellow-tailed blue damsel x3
Coral beauty
Coral: around 15 small pieces of various types (healthy as far as I can tell)
CUC: blue, red, scarlet hermit crabs (25?), probably 15 snails Astrea and Trochus.
Summarizing my experience to date. I bought a cheap Orapxi salinity checker when I got the tank, and measured it weekly with water changes etc. I was naive and didn’t know these things need calibration (my bad).
9 months ago, when I redoubled my maintenance and “tank improvement” efforts, I sent off an ICP. Orapxi said 35, ICP said 31.5. Not good, need to recalibrate.
After some research, I purchased a refractometer (brand Autoutlet). I was/am aware they also need calibration and did/do so regularly with both rodi (make sure it reads zero) and a calibration fluid (35ppt). I start with the rodi, set that to zero, then use the calibration fluid and set that to 35… then measure whatever I’m measuring for the week. I also let the refractometer acclimate to roughly water temperature (I’m in Houston, so my water change water can be 90 degrees). This seemed to work better and I had a few ICP tests that were all in line. Great.
My most recent ICP says the tank is back down to 32ppt. The refractometer says today (and at the same time I took the ICP a week ago)… 35ppt. The Orapxi, which I hold on to reasons I can’t explain, says 32. So… break out a new vial of the calibration fluid. The refractometer says 35. The Orapxi, in true form, says 44. :-)
Out of the options… I trust the ICP. I do not trust any of the tools I have (Orapxi, refractometer, and/or the calibration fluid). I really just want a process to measure salinity that will allow me to remove it from the uncertainty/concern bucket… so that I can move on to other ICP issues (high Aluminum, moderate phosphate, and a wild dearth of trace elements caused by my refugium).
I appreciate your time, experience, and opinions. Additional detail provided below in case it is helpful.
Other common questions:
How does the reef look? Looks the best it ever has, except for one hammer I clipped with my knuckle a week ago… and that refuses to forgive me. Fish are normal. Coral color is good. Coral extension is good. I have some gha that is driven by elevated nutrient levels, and I’m working on that (nitrate 19, phosphate 0.13). The gha is still in check.
What equipment do you have? Red Sea skimmer/lights/ato/reefmat. Phytotank (refugium in a bottle). I’m running a bit of gfo (1/3 cup), mixed with 2/3 cup carbon.
Is it possible you under filled the tank with saltwater and topped up a lot with ATO water instead after the water change? Possible, for sure, but I don’t think it happened this time. I checked the ato log (I use the Red Sea ato+), and it shows normal consumption on that day. Also, I took the ICP sample and did my own refractometer test at the same time… so they should have both been low if that happened.
What is your water change process? Mix 35 gallons of rodi in a trash can in the backyard, add Red Sea salt (blue bucket), and let it run for a day with a small power head and a sicce 2.0 with no hoses attached (just blasting water around). Once I’ve tested it with the refractometer and dialed it in with fresh rodi (and more testing) and let that mix, I run it through a sediment filter and add it to the tank. I change about 10 gallons a week. Later in the maintenance process I check the salinity in the DT to make sure it’s not out of whack.
Full weekly testing suite… but these are all the ICP result values:
Salinity ICP says 32.
PH 7.8
Nitrate 19
Phosphate 0.13 (this is the ICP number, and could reasonably be the subject of a companion post. My Hanna checker is my fifth test kit for phosphate, says 0.18, and api and Fritz both say as they have since day one, 0.50).
ALK: 7.3
Calcium: 395
Magnesium: 1314
Iodine: 0.07 (salifert said < 0.01)
ICP also indicated very low trace elements across the board, except for Aluminum which is very high. I presume it’s from my gfo (h33 bayoxide) and I may not have rinsed it enough. Unclear.
Livestock:
Fox face rabbit fish
Generic clown fish x2
Royal gamma
Flame hawk fish
Yellow-tailed blue damsel x3
Coral beauty
Coral: around 15 small pieces of various types (healthy as far as I can tell)
CUC: blue, red, scarlet hermit crabs (25?), probably 15 snails Astrea and Trochus.
