Parameters on the up? 🤔

[Murphs_Reef]

Help me understand this then. 

Been watching this recently unfold, initially thought it was just sloppy testing.. and recorded it anyway.

2 weeks ago became more interested and puzzled. So fully cleaned down all testing equipment and retested to the same values. 

No change in salinity, no water changes, just top up with RODI (at 2 TDS). 

Only thing dosed has been 1ml of Reef Zlements Z-PhosPlus daily as I struggle to keep phosphate up above 0.00. 

 

Salifert Test kits are all in date expiring as below: 

 

All numbers have been on the up. 

• Alk now 10.4 was a stable 9.2 
• Calcium 500, was between 420 and 450
• Mag I have at 1500 but exceeds the salifert test range and could be 1600, was 1420. 

 

Temp is 25°c 

Phosphate steady 0.06ppm

Nitrate 5pmm

Salinity 1.025ppm

 

Coral and fish all fully extended / active. 

If it continues to go up I'll end up with a big white brick tank 🤣 

All LPS is growing fine. SPS is the same.. in fact the plating Monti's are growing so fast they are brittle and the slightest brush past fractures them... 

AND I have decent coralline growth so elements are being consumed!? 

 

Help me understand, find the root cause?

 

Example of parameters before the upturn:

Temp: 25 °C

NO3 (Salifert): 5.0 ppm

PO4 (Hanna): 0.02 ppm

SG (TMC): 1.025 SG

Alk (Salifert): 9.1 dKH

Ca (Salifert): 450 ppm

Mag (Salifert): 1420 ppm

[Pjanssen]

Hmmm 🤔?  You're sleep walking and dosing then?

 

Honestly I have no idea, certainly is a puzzle and I'm curious to see what others in the know have to say.

[empresto]

Could always get a reference solution like the following and test against a known value: https://www.bulkreefsupply.com/fauna-marin-multi-reference-solution.html

 

My question would be when you last calibrated your refractometer.  A steady salinity rise would explain what you're seeing. The above reference solution is what I calibrate my refractometer with.

[Murphs_Reef]

Thanks @empresto. I calibrate before every use with RODI, although it's supposed to have automatic temperature compensation, I don't trust it 

[empresto]

Yeah, the temperature compensation is really only to flatten out measurements when the sample is at a temp other than room temp, like our tanks. This is different than calibrating the instrument, which sets the measurement scale relative to a known measurement.

 

You did mention your rodi is at 2ppt tds, what is the possibility that the container you are getting rodi out of for calibrating your refractometer has been accumulating tds over time, this causing your calibration to read lower than actual?

[Murphs_Reef]

26 minutes ago, empresto said:

Yeah, the temperature compensation is really only to flatten out measurements when the sample is at a temp other than room temp, like our tanks. This is different than calibrating the instrument, which sets the measurement scale relative to a known measurement.

 

You did mention your rodi is at 2ppt tds, what is the possibility that the container you are getting rodi out of for calibrating your refractometer has been accumulating tds over time, this causing your calibration to read lower than actual?

I did think of that as well so washed that out. Then when it was dry i did the TDS on that as well as check the top off chamber in the sump. It's all 2 TDS. It's very odd. I don't want to mix up new salt and change any water out as everything is happy. If I make any sudden changes I'm sure it will rock the boat. 

 

I will get some of the calibration fluid and go from there, though saying that the magnesium test kit is new last week and that was reaching the same result as the old one.

In terms of timeline, Mag starting moving up first then the alk and calcium followed the upward trend. I can't think for the life of me what's changed.. looking at external factors as well.. 

[M. Tournesol]

15 minutes ago, Murphych said:

I can't think for the life of me what's changed.. looking at external factors as well.. 

end of a bucket of salt?

[Murphs_Reef]

21 minutes ago, M. Tournesol said:

end of a bucket of salt?

No I don't do water changes at all. Just top offs with fresh water 

[M. Tournesol]

46 minutes ago, Murphych said:

No I don't do water changes at all. Just top offs with fresh water 

strange ... the only physical thing that I could think of is a change in your average ph level that would up your Kh, Calcium and Mg level.

[DaJMasta]

Do you calibrate your refractometer with RODI or with a known salinity solution?  The latter is usually recommended and is always preferred and is available fairly cheap.  You shouldn't be recalibrating it every time either, once every few months is plenty.

 

I would give your test kit vials a thorough clean and then see if the trend continues.  As you are puzzled as well, you're seeing increases in things that don't really leech out and can't possibly be added by top off with just a 2ppm total TDS, even if those 2ppm are all calcium and carbonate.  My assumption would be that either the test methodology is changing or the equipment used is getting grimy and that is changing the readings.

 

If you actually aren't dosing and aren't doing water changes in the period pictured, I'm almost wondering if you're reading the inverse value on titration tests or something so that the trend is actually the opposite of what you're getting.  If your stony corals and coralline are growing and you are not dosing anything, your alkalinity and even calcium should be going down noticeably.

As a sanity check, as it could cause this, you're not adding any kalkwasser to your top off, right?  And your top off vessel is clean?

[Murphs_Reef]

3 hours ago, DaJMasta said:

Do you calibrate your refractometer with RODI or with a known salinity solution?  

 

As a sanity check, as it could cause this, you're not adding any kalkwasser to your top off, right?  And your top off vessel is clean?

Thanks for your input. 

I use RODI to calibrate down to 0. Always have done it this way for years, as this is the only way I knew of when I started in salt water. So figured it has always worked so never changed it? 

 

Yeah correct no dosing of any kind other than phosphate. Which I have checked on the manufacturer site for extra ingredients. 

 

I clean out all of my gear very well with tap water when I'm done with it (so to improve the life expectancy of the item being used) then rinse with RODI when done. 

 

In all my years I have never seen calcium over 450.. yeah my alk has been up at 12 in the past but only due to errors in overdosing pH up (a few of years ago in another tank). 

 

I have even checked the frozen mysis blocks ingredients today lol!! Knowing that is never going to be a thing!!! 🤣

 

I'll get the solution @empresto suggests. But other than that either my wife has done a lot of secret research and is messing with me or I'm going crackers. 

Just rerun the tests later this afternoon to check while the lights where ramped right up and it's exactly the same numbers.. 😱

[Murphs_Reef]

The upturn was first observed on 19th July going off the data behind the graphs and after the 10th. Just been through my build thread and offline notes to see if I had changed anything during that timeframe... Nothing... Around the house nothing changed either that I can recall.  

[Murphs_Reef]

Ordered the calibration fluid yesterday so should be here by the time I finish work today. 

[Murphs_Reef]

Yeah so test solution / calibration fluid came and confirmed. 

Retested and have:

• Alk now 10.5
• Calcium 500
• Mag 1500 

We are most definitely on the up......

[empresto]

Did you test your refractometer with the reference solution?

[Murphs_Reef]

10 hours ago, empresto said:

Did you test your refractometer with the reference solution?

Yeah it was fine, it was set to 35 (1.026?) and my water sample was just under at 1.025 which is where I expected it to be. 

 

I just can't think what's changed either internally it externally to be pushing this up.. I even spent all day yesterday watching how often the wife opens and closes windows #clutching-at-straws.....

[M. Tournesol]

You should set up a spy camera 🤣

[Murphs_Reef]

I don't know. Just tested again after cleaning everything down one last time. Sump cleaned down and new carbon added, new sock and skimmer cleaned out...not that they cause CA, Mag and alk parameters to go up ... All tests show as high as yesterday...

 

Give up....

[M. Tournesol]

Your problem sure is frustrating. 

If the corals don't seem to be perturbed you should just ignore it.

[Murphs_Reef]

2 minutes ago, M. Tournesol said:

Your problem sure is frustrating. 

If the corals don't seem to be perturbed you should just ignore it.

Yeah I'm not going to do anything for now. It just don't make sense at all. 

[Murphs_Reef]

From a post on R2R I have been reading through Randy Holmes-Farley, suggests that one cause could be dissolution of live rock or sand due to very low tank water pH...

 

I haven't measured pH for a long time.. I'll do that tomorrow I think. 

[Murphs_Reef]

And of course the one change I didn't document was... Oh hold on that white rock is new!? Like a month new 

[Murphs_Reef]

pH is 8.4 so Christ knows then... Measured alk at 10.5 and calcium at 480... So calcium has reduced a bit but.....

[Bigals-nano-1]

3 hours ago, Murphych said:

pH is 8.4 so Christ knows then... Measured alk at 10.5 and calcium at 480... So calcium has reduced a bit but.....

Just a thought…..could it have been a partial blockage/ ca and mg deposits in a piece of piping which had built up then cleared its into the tank which caused the sudden rise?

just a stab in the dark……

[Murphs_Reef]

36 minutes ago, Bigals-nano-1 said:

Just a thought…..could it have been a partial blockage/ ca and mg deposits in a piece of piping which had built up then cleared its into the tank which caused the sudden rise?

just a stab in the dark……

God knows dude