Help with high KH, Calcium and Magnesium

[maff2026]

35 gallon tank, arragonite 3 inch deep, coral rock and tufa rock.
PH 8.3
Calcium 540
Magnesium 1600
KH 15
Tank been operational with no fish for about a week using instant ocean salt.
Thanks.

 

[Uncle99]

35 gallon tank, arragonite 3 inch deep, coral rock and tufa rock.
PH 8.3
Calcium 540
Magnesium 1600
KH 15
Tank been operational with no fish for about a week using instant ocean salt.
Thanks.

Whats salinity?
Should be hard to get those results in a week unless your adding something.
Salinity affects all of those….
If it’s more than 35ppt, then all else will follow same.
Which test kits?

 

[maff2026]

Whats salinity?
Should be hard to get those results in a week unless your adding something.
Salinity affects all of those….
If it’s more than 35ppt, then all else will follow same.
Which test kits?

1024 sg and NT Labs marine test kit

 

[Uncle99]

1024 sg and NT Labs marine test kit

Doesn’t make sense.
Never heard of that kit.
Get good ones, those numbers seem odd.

Did you use a refractometer on the salinity?

 

[maff2026]

Doesn’t make sense.
Never heard of that kit.
Get good ones, those numbers seem odd.

Did you use a refractometer on the salinity?

No I've got an hydrometer which I've tested on ro water and is quite accurate.
Could the fact I've turned off my oxygen producing devices have an effect on the readings. I haven't had my power head breaking the surface and my skimmer is off because there is no nitrate or phosphates in the water.
Should I test after a few hours of oxygenating?

 

[maff2026]

Right, with oxygen in the water, the calcium has tested to 420, the magnesium is 1400 and the KH is 12.
Just read that these coloured test kits need at least 2ppm oxygen or they read innacurate and they do indeed.

 

[Randy Holmes-Farley Verified Community Expert]

Right, with oxygen in the water, the calcium has tested to 420, the magnesium is 1400 and the KH is 12.
Just read that these coloured test kits need at least 2ppm oxygen or they read innacurate and they do indeed.

This doesn't make sense. There may have been test kit error or salinity errors before or now, but alk, calcium, and magnesium test methods do not require ANY oxygen in the water.

I'm not sure where you are getting this info from, but I'd look elsewhere for chemical advice. :)

 

[maff2026]

This doesn't make sense. There may have been test kit error or salinity errors before or now, but alk, calcium, and magnesium test methods do not require ANY oxygen in the water.

I'm not sure where you are getting this info from, but I'd look elsewhere for chemical advice. :)

I'm wrong with it. It doesn't alter the test result. It changes the parameters of the water which the test kit picks up on. I haven't had my oxygenators running for days and CO2 will have been higher. After I oxygenated the water for an hour it changed the results slightly.

 

[maff2026]

Doesn’t make sense.
Never heard of that kit.
Get good ones, those numbers seem odd.

Did you use a refractometer on the salinity?

I've just ordered a refractometer. I've calibrated my hydrometer in RO water once again and you can't get a good reading because the surface tension is blocking the reading, i'm not entirely sure whether to read above the surface tension bend or below it and there is quite a difference between the two readings so I'm going to get a refractometer and calibrate it properly. The DO in the water believe it or not does affect the NT Labs results.
NT Labs is a UK based company I've used for many many years and all my electronic meters have always tallied with NT results and I trust them.

 

[exnisstech]

Instant ocean salt always mixes a little over 9dkh at 1.025 salinty for me something is awry.

 

[maff2026]

Instant ocean salt always mixes a little over 9dkh at 1.025 salinty for me something is awry.

I think personally my hydrometer readings are off the mark and I may be at 1026 or higher which would explain it.
Also, couple that together with the fact I had no dissolved oxygen in the tank which was full of CO2 at the time would also affect the results. Oxygenating the water has made a difference and it does warn you that elevated CO2 levels may affect your KH readings.
I can't set the correct SG till the refractometer arrives and is calibrated. Then we will see how far the glass hydrometer is out.

 

[maff2026]

I think there have been a few errors on my part using the test kit properly which hasn't helped.
But at least I'm getting all this stuff out of the way with nothing in the tank.
The hydrometer water tension problem is horrendous. On the bottom of the tension bend the reading is 1027, at the top of the bend is 1025 and in the middle of the bend is 1026 and I've been using the 1025 reading which may be wrong. If I put something in the water to remove the tension then I change the SG.
This is what happens when you get to 60 lol.
Just get the refractometer, keep the water oxygened and start again lol.
Thanks all for the input.

 

[Fish Fan]

I haven't had my oxygenators running for days and CO2 will have been higher.

Could I please ask, what do you mean by an "oxygenator"? An air pump?

I've calibrated my hydrometer in RO water once again and you can't get a good reading because the surface tension is blocking the reading, i'm not entirely sure whether to read above the surface tension bend or below it and there is quite a difference between the two readings so I'm going to get a refractometer and calibrate it properly. The DO in the water believe it or not does affect the NT Labs results.
NT Labs is a UK based company I've used for many many years and all my electronic meters have always tallied with NT results and I trust them.

There's nothing to calibrate on a hydrometer, are you sure you're taking about a glass hydrometer? If so, you read it where the surface of the water is, you ignore the surface tension, like this:

I know my Tropic Marin hydrometer needs to have the water temp at 77F/25C to be accurate.

I have used the NT labs test kits for freshwater and thought they were decent enough for that, but my gut feeling is that for saltwater they are on par with something like the API brand test kits; good, but far from great. Check out the Salifert kits, they are inexpensive and generally regarded as quite dependable.

I hope this helps!

 

[Uncle99]

I think there have been a few errors on my part using the test kit properly which hasn't helped.
But at least I'm getting all this stuff out of the way with nothing in the tank.
The hydrometer water tension problem is horrendous. On the bottom of the tension bend the reading is 1027, at the top of the bend is 1025 and in the middle of the bend is 1026 and I've been using the 1025 reading which may be wrong. If I put something in the water to remove the tension then I change the SG.
This is what happens when you get to 60 lol.
Just get the refractometer, keep the water oxygened and start again lol.
Thanks all for the input.

Once you have a good read on salinity to 1.026, then test again.
Might be an idea to test freshly mixed salt as well to ensure is correct.
I’ve not used those but you’d know better than me, always like to rule out kits first.
Some are next to useless.

 

[maff2026]

Could I please ask, what do you mean by an "oxygenator"? An air pump?


There's nothing to calibrate on a hydrometer, are you sure you're taking about a glass hydrometer? If so, you read it where the surface of the water is, you ignore the surface tension, like this:

I know my Tropic Marin hydrometer needs to have the water temp at 77F/25C to be accurate.

I have used the NT labs test kits for freshwater and thought they were decent enough for that, but my gut feeling is that for saltwater they are on par with something like the API brand test kits; good, but far from great. Check out the Salifert kits, they are inexpensive and generally regarded as quite dependable.

I hope this helps!

The problem is the water tension isn't just at the sides like the picture, its in between the hydrometer and the observer to such a degree I can't see an awful lot and the tension bend is much bigger than the one pictured. The tension blanks everything out from 1025 to 1027 into a complete blur. Its off in the bin.

 

[maff2026]

Could I please ask, what do you mean by an "oxygenator"? An air pump?


There's nothing to calibrate on a hydrometer, are you sure you're taking about a glass hydrometer? If so, you read it where the surface of the water is, you ignore the surface tension, like this:

I know my Tropic Marin hydrometer needs to have the water temp at 77F/25C to be accurate.

I have used the NT labs test kits for freshwater and thought they were decent enough for that, but my gut feeling is that for saltwater they are on par with something like the API brand test kits; good, but far from great. Check out the Salifert kits, they are inexpensive and generally regarded as quite dependable.

I hope this helps!

Could I please ask, what do you mean by an "oxygenator"? An air pump?

My oxygenating system is the skimmer partially and my UV power head which gives plenty of surface movement and has air inclusion, my wave maker isn't doing it as yet.
I didn't have any of them running for 2 days because I was working on the tank at the time so CO2 was more than likely very high with a few people being in the room over the two day period.

 

[maff2026]

When I said calibrate the hydrometer I meant check the reading was correct with tap water and RO water.
Initially at room temperture tap water was bang on the money at 10.00.
I've just done some further testing with RO water and tap water at room temperature and tap water shows 10.00 but RO water is showing 00.90.
A significant difference. I'm no longer confident in its ability to give an accurate salinity measurement.
Surely it should show 10.00 for RO water?
If it hasn't been calibrated properly, my salinity could be as high as 10.35?

 

[exnisstech]

Maybe look into a conductivity meter? I have not used one but @Randy Holmes-Farley likes them from what I've read and may have recommendations on one?

 

[maff2026]

Maybe look into a conductivity meter? I have not used one but @Randy Holmes-Farley likes them from what I've read and may have recommendations on one?

I've ordered the refractometer which should tell me what this piece of rubbish is up to.
Yorkshire water who supply my water are known to have high TDS which changes at certain times of the day because of demand. Its different on a morning before everyone wakes up because the system is using 60 year old iron pipes and it increases the TDS during the night. I've measured this with my TDS meter and found swings.
If the TDS is at its highest it could affect the readings on an hydrometer compared to how the hydrometer was originally calibrated and where.
The fact that tap water shows as 10.00 and RO water shows at 00.90 tells me they made a mess of calibration and the chart inside the hydrometer itself may add to innacuracies too.
I'll personally enjoy taking the hammer to this hydrometer when the refractometer arrives.

 

[exnisstech]

Do you have an image of the refractometer you have? Asking only because I have the tropic Marin one and using it in a graduated cylinder it has been easy for me to read and I don't have the best eye sight. Just throwing it out because you mentioned earlier of having trouble reading your hydrometer.

PS. I'm sure your aware but you'll need to calibrate the refractometer. Using RO is not recommended for most so you'll need a known good calibration fluid or you'll be back in the same boat.