I give up!

Mr31415

Mr31415

Active member
I have posted on this before here and here, yet I am still struggling.

Basic background:
Tank Size: 90g
Type: Mixed reef (20% LPS, 80% Softies)
Coralline: Good growth of coralline algae
Topup: Tunze auto topup RO through Deltek kalkstirrer
SG: 1.026 (ATC refractometer)
Alk: 5.0 - 6.5 dKH (D-Deltec)
Ca: 420mg/L (D-Deltec)
Mg: 1480mg/L (D-Deltec)
Temp: 24.5C - 27C (controller, electronically monitored)
pH: 8.00 - 8.25
Salt Mix: D-Deltec H2Ocean
NO2: 0
NO3: 0
P: <= 0.008mg/L (D-Deltec Low Range)
Tank Age: 1 year 2 months
Picture and live stock: Here.
Lights: 2 x 250W MH
Evaporation: Not sure but I do need to refill my 20L RO container every 10 days or so.

My problem? I am not sure it is possible to accurately measure Alk, Ca and MG. Look at my results (all test kits still valid - not yet expired):

D-Deltek
=====
Alk: 6.2 dKH
Ca: 420mg/L
Mg: 1480mg/L

Elos
===
Alk: 5.0 dKH
Ca: 550mg/L
Mg: 980mg/L

Salifert
=====
Alk: 6.4dKH
Ca/Mg: Do not own these kits

I have no idea what to trust. Elos, Salifert and D-Deltec are supposed to be the better hobbyest test kits around. They certainly are more expensive. Yet they cannot agree on the same numbers. Not even close.

I am 100% confident I am performing the tests correctly. It is not like I have not spent the past 6 years keeping reef aquariums and been testing ever since.

The tank itself looks normal. I mean, fish are healthy, inverts seem 100% ok except for some losses which I am very confident are due to predation and not water parameters as I have several inverts doing extremely well for the past 1 year. Corals are healthy. I have good polyp extension. My clam died after 10 months, and this is what prompted me to consider my persistent low alkalinity levels.

I need to clean coralline growth off the window panes weekly, so my Calcium levels cannot be too bad.

So what am I to do? Last time I trusted my Elos Mg test kit and added magnesium supplement all my corals bleached. So I am confident 980mg/L is wrong. If I am to trust the D-Deltec, then why, with Mg = 1480mg/L and Ca = 420mg/L, can I not keep my Alkalinity up? I dosed Kent Pro dKH buffer daily, about 40mL per day, and I see my Alkalinity raise from 5.6dKH to about 6.4dKH, then if I leave the tank be for 48 hours it will be back at 5.6dKH. I cannot see the coral consuming 1dKH in 2 days, keeping in mind I am dosing kalkwasser through my ATO.

So my questions:

1) Where can I find a lab grade saltwater test kit for Alk, Ca and Mg? I was thinking Merck - any opinions?
2) How on earth do I raise and maintain a high alkalinity? Do I need to switch salt brands? I thought D-Deltec's H2Ocean would be of higher quality than Instant Ocean.
 
Your not to far off. Just bring up Alk a little. Leave everything else alone. Rather be a little low in MG than to add to much. Look at corals see how they doing. Instead of dosing do water changes so you don't kill stuff.
 
Mr31415 said:
I have posted on this before here and here, yet I am still struggling.

Basic background:
Tank Size: 90g
Type: Mixed reef (20% LPS, 80% Softies)
Coralline: Good growth of coralline algae
Topup: Tunze auto topup RO through Deltek kalkstirrer
SG: 1.026 (ATC refractometer)
Alk: 5.0 - 6.5 dKH (D-Deltec)
Ca: 420mg/L (D-Deltec)
Mg: 1480mg/L (D-Deltec)
Temp: 24.5C - 27C (controller, electronically monitored)
pH: 8.00 - 8.25
Salt Mix: D-Deltec H2Ocean
NO2: 0
NO3: 0
P: <= 0.008mg/L (D-Deltec Low Range)
Tank Age: 1 year 2 months
Picture and live stock: Here.
Lights: 2 x 250W MH
Evaporation: Not sure but I do need to refill my 20L RO container every 10 days or so.

My problem? I am not sure it is possible to accurately measure Alk, Ca and MG. Look at my results (all test kits still valid - not yet expired):

D-Deltek
=====
Alk: 6.2 dKH
Ca: 420mg/L
Mg: 1480mg/L

Elos
===
Alk: 5.0 dKH
Ca: 550mg/L
Mg: 980mg/L

Salifert
=====
Alk: 6.4dKH
Ca/Mg: Do not own these kits

I have no idea what to trust. Elos, Salifert and D-Deltec are supposed to be the better hobbyest test kits around. They certainly are more expensive. Yet they cannot agree on the same numbers. Not even close.

I am 100% confident I am performing the tests correctly. It is not like I have not spent the past 6 years keeping reef aquariums and been testing ever since.

The tank itself looks normal. I mean, fish are healthy, inverts seem 100% ok except for some losses which I am very confident are due to predation and not water parameters as I have several inverts doing extremely well for the past 1 year. Corals are healthy. I have good polyp extension. My clam died after 10 months, and this is what prompted me to consider my persistent low alkalinity levels.

I need to clean coralline growth off the window panes weekly, so my Calcium levels cannot be too bad.

So what am I to do? Last time I trusted my Elos Mg test kit and added magnesium supplement all my corals bleached. So I am confident 980mg/L is wrong. If I am to trust the D-Deltec, then why, with Mg = 1480mg/L and Ca = 420mg/L, can I not keep my Alkalinity up? I dosed Kent Pro dKH buffer daily, about 40mL per day, and I see my Alkalinity raise from 5.6dKH to about 6.4dKH, then if I leave the tank be for 48 hours it will be back at 5.6dKH. I cannot see the coral consuming 1dKH in 2 days, keeping in mind I am dosing kalkwasser through my ATO.

So my questions:

1) Where can I find a lab grade saltwater test kit for Alk, Ca and Mg? I was thinking Merck - any opinions?
2) How on earth do I raise and maintain a high alkalinity? Do I need to switch salt brands? I thought D-Deltec's H2Ocean would be of higher quality than Instant Ocean.
Click to expand...


1dkh in 2 days is nothing. I know some tanks that consume 2dkh a day. My old 40g tank was using up about 1 dkh every 1-2 days.

Go get some standard Baking Soda from the store and dose that to up your levels. You will have to find the recipe to use. I don't have a link on this computer.
 
I'm going through the same thing. My tank is mostly sps and I have to dose alkalinity daily. I do this manually but I have just ordered a dosing pump. I use alk solution from BRS, pretty cheap.
 
As I said in the other thread, it's fairly common for tanks to need more than just limewater for supplementation. I'd just dose some baking soda every day, as suggested. A few days should give a reasonable trend line. I'd start by dosing the tank up to 8 dKH in two doses, one in the morning and one in the afternoon.

The alkalinity results are all reasonably close, given all the issues involved. I've never used those calcium or magnesium kits, so I can't help there.
 
Mr31415 said:
yet I am still struggling.
D-Deltek
=====
Alk: 6.2 dKH
Ca: 420mg/L
Mg: 1480mg/L

Elos
===
Alk: 5.0 dKH
Ca: 550mg/L
Mg: 980mg/L

Salifert
=====
Alk: 6.4dKH
Ca/Mg: Do not own these kits

I have no idea what to trust. Elos, Salifert and D-Deltec are supposed to be the better hobbyest test kits around. They certainly are more expensive. Yet they cannot agree on the same numbers. Not even close.

I am 100% confident I am performing the tests correctly. It is not like I have not spent the past 6 years keeping reef aquariums and been testing ever since.

The tank itself looks normal. I mean, fish are healthy, inverts seem 100% ok except for some losses which I am very confident are due to predation and not water parameters as I have several inverts doing extremely well for the past 1 year. Corals are healthy. I have good polyp extension. My clam died after 10 months, and this is what prompted me to consider my persistent low alkalinity levels.

I need to clean coralline growth off the window panes weekly, so my Calcium levels cannot be too bad.

So what am I to do? Last time I trusted my Elos Mg test kit and added magnesium supplement all my corals bleached. So I am confident 980mg/L is wrong. If I am to trust the D-Deltec, then why, with Mg = 1480mg/L and Ca = 420mg/L, can I not keep my Alkalinity up? I dosed Kent Pro dKH buffer daily, about 40mL per day, and I see my Alkalinity raise from 5.6dKH to about 6.4dKH, then if I leave the tank be for 48 hours it will be back at 5.6dKH. I cannot see the coral consuming 1dKH in 2 days, keeping in mind I am dosing kalkwasser through my ATO.

So my questions:

1) Where can I find a lab grade saltwater test kit for Alk, Ca and Mg? I was thinking Merck - any opinions?
2) How on earth do I raise and maintain a high alkalinity? Do I need to switch salt brands? I thought D-Deltec's H2Ocean would be of higher quality than Instant Ocean.
Click to expand...

1) I think you are over thinking this and stressing out over small details. I agree the tests you quoted had quite different mag readings. But then you said, "Last time I trusted my Elos Mg test kit and added magnesium supplement all my corals bleached." I'm no expert, but I've never heard of elevated mag readings bleaching corals. In fact it's a common tool (mag of 1700-1900ppm) used against some problem algaes and that doesn't bleach corals. I use API and Salifert test kits and most of the time they have very similar results (nitrate, calcium, alk).

2) You asked, "How on earth do I raise and maintain a high alkalinity?" how about dosing... more. I have a 180g DT that is fairly well stocked with a variety of corals and I dose 200ml of calcium and 225ml of soda ash every day! 40ml a day into your 90g DT isn't that much if you have a good population of corals and other invert users.
 
Ron Reefman said:
I'm no expert, but I've never heard of elevated mag readings bleaching corals. In fact it's a common tool (mag of 1700-1900ppm) used against some problem algaes and that doesn't bleach corals.
Click to expand...

Thanks for the good advice. Just a note on this comment - I have proven it thrice now that highly elevated Mg levels will bleach coral. I did this way back in 2007 I think when I had bryopsis, and dosing magnesium supplements did the exact same thing - they bleached some corals. Nothing else changed except for me raising magnesium, then (some species of) corals bleached.
 
bertoni said:
The alkalinity results are all reasonably close, given all the issues involved. I've never used those calcium or magnesium kits, so I can't help there.
Click to expand...

If you say you've never used "those calcium / mg kits" - are you talking about brands or never tested for Calcium / Mg at all? If the latter, how do you ensure your Ca/Alk balance is maintained?
 
Mr31415 said:
Thanks for the good advice. Just a note on this comment - I have proven it thrice now that highly elevated Mg levels will bleach coral. I did this way back in 2007 I think when I had bryopsis, and dosing magnesium supplements did the exact same thing - they bleached some corals. Nothing else changed except for me raising magnesium, then (some species of) corals bleached.
Click to expand...

Just to be clear, that suggests that something bleached the corals when you raised magnesium, but not necessarily the magnesium itself.

As has become apparent from the Tech M for bryopsis issue, it isn't the magnesium that seems to kill bryopsis, but rather something in some brands of supplements that are not present in others.

So that same issue may pertain to your bleaching experiences. :)
 
Touché. PS: Good to see you posting in this forum again (I was away for a bit... last I saw you left).
 
If you don't mind spending a little get a GEO calcium reactor and a masterflex pump to run it. I constantly had trouble maintaining my alk even with a dosing pump for two part. I stepped up to a calcium reactor and a masterflex and have not looked back. Now I set it and forget it for 6 months. Check out eBay for a masterflex, you should be able to get one for under $200. You can even dose mag in your calcium reactor at the same time.
 
Mr31415 said:
I have no idea what to trust. Elos, Salifert and D-Deltec are supposed to be the better hobbyest test kits around. They certainly are more expensive. Yet they cannot agree on the same numbers. Not even close.
Click to expand...

Your question is the same as many other hobbyists ask in the Chemistry Forum. This includes all the test kits we use available as hobby grade. Each manufacturer claims their kits are accurate. Without going into all the chemistry involved it is impossible to ascertain which kit would be the most accurate in your particular tank system.

There are other variables involved which can throw off the test results & perhaps some of the test kits may account for some of these factors within the design of their kit. These hobby grade test kits can't account for all the possible factors (which throw off results) found in a reef aquarium when trying to determine the various parameter levels that we can measure.

For the most part, we hobbyists do not know what the borate level is in our tank. Some hobbyists dose borates in supplements. Some salt mixes may be high or low in borate, we know this from some simple experiments we have seen completed in the past. Borate is included in the final outcome of the alk tests used.

Suspended calcium carbonate is another source of interference for alk & to some degree calcium test kits. All tanks have suspended calcium carbonate according to the results seen from what is removed using skimmers. As Boomer has pointed out, there are possibly a lot of supplements that hobbyists use which contain chemicals that can interfere with alk kits results. Dosing aragonite powders would be an example of this.

The micro-organisms in our tank can have levels of calcium carbonate as well, which can throw off our results.

Habib has pointed out that using sulfuric acid instead of hydrochloric acid in alk test kits can account for some error depending on the interference of other chemicals in our tank.

As test kits age, things evaporate out of the reagents used especially if the tops are allowed to remain off for longer periods of time, which reduces the accuracy of the kits.

This list goes on.

Even when tests are completed in the lab, there are discrepancies among the lab scientists regarding proper test procedures & methods. This has evolved over the years to which test procedures and methods which are currently used. Error still exists even using the most expensive equipment.

The testing procedures used by the hobbyists for these hobby grade test kits can vary considerably. Determining the final end point when color changes occur can be viewed differently by each hobbyist. This has been seen at my club when we provided a seminar on how to use these kits. It was not surprising that hobbyists had discrepancies of 2 dKH using the same kit and sample. Its nice that some manufacturers provide standards now, which helps educate hobbyists for determining the final end point, though there may be expiration dates for these standards. Also, as Habib has pointed out that many hobbyists do not understand how to properly mix the solution after adding each drop of the titrant. Without proper mixing, this can cause quite a bit of error.

Luckily, according to the research I have read, alk levels between 6 dKH up to 18 dKH (possibly higher & lower) are not a problem for most coral. The recommended level is 7-11 dKH which was established for various reasons. If your alk level becomes too low your coral will suffer. Something to take into consideration when you choose to keep your alk level at the lower end regarding test kit errors. If your alk level becomes to high, than you will experience too much calcium carbonate precipitation on your tank glass and equipment. Something to take into consideration if you choose to keep your alk level at the high end. Using these visual ques can help to make sure your alk level is within the recommended guidelines when taking alk kit error into consideration.

Calcium levels in reef tanks can vary from 350 ppm to over 500 ppm without problems. So you have quite a range to shoot for.

The same applies with magnesium levels. Ranges between 1200 - over 1600 ppm don't to seem to be problematic. So, again you have quite a range to shoot for.

My recommendation is to shoot for the middle of the recommended alk range (7-11 dKH), which should keep you in a good region for an alk level taking into consideration the needed carbonate/bicarbonate for proper coral growth & test kit error for all the various reasons noted above. Calcium, shoot for over 400 ppm and you should be in good shape. magnesium shoot for over 1300 and you have plenty of room for error.

I believe that consistency in proper test kit procedure and maintaining an alk level within reason is the most important aspect.
 
In my experiences ELOS ALK kits always test lower then most others. My salifert and my Hanna match, my elos was lower. I went threw the same frustration as you. What's more important then the number is constancy. I decided since I can't trust any kit. I'm going to run my parameters right in the middle of the road. So if I'm +/- any "reasonable" amount. I'm going to be ok.

I'm using hanna kit for ALK and shoot for a consistent 9-9.5 which means if +/- 1 I'm still fine.

and I use Salifert for Calc and Mag. I shoot for 350-400 for calcium. +/- 50 wouldn't matter.

and I shoot for 1350-1400 for mag again +/- 50 wouldn't matter.

As long as from test to test things seem to hold similar numbers I don't worry about it, and unless something went horrible wrong (some sort of obvious organic issue like something big dying or mechanically failure) I try to avg my numbers throwing out a single random high or low that may be a result of testing errors.
 
Last edited:
I have successfully raised my Alkalinity to 9dKH using about 5 teaspoons of baked baking soda in total over a couple of days. Will monitor daily consumption and report back.
 
Yeah I did mention it was "baked baking soda". Heated in oven at 350F for 1 hour to drive out the moisture.
 
The alk boost is the same (when the amount of additive is weighed before baking). Baking it first also makes it boost pH, not just alk. :)
 
Last edited:
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