Really high GH and SW mixes

[Jayhawk]

In another thread where I was trying to figure out why my SG is at 1.005 when using 1 rounded (probably 1 and 1/3) tablespoons of Instant Ocean per gallon, I decided to test all my water parameters and found a really high GH. Here are the numbers:

Nitrites 0
Ammonia 0
Nitrates 20ish (just less in color than the 25 mark)
KH 7 (retested today, this is thanks to an argonite substrate)
GH 59
pH 7.8

My tap water is:
Nitrite and Ammonia - didn't test
Nitrates 12.5
KH 2
GH 12
pH 7.6

I'm amazed by the GH increase. So I tested some BW in the bucket before adding to the tank (to make sure the rocks or substrate weren't causing the problem) and the GH in the bucket was over 45 - I stopped testing to save on the drops when I realized it was the instant ocean increasing the GH so much.

I've never been overly concerned about GH before, and I wonder should I be now?

Anyone else who uses Instant ocean willing to test the GH of their tap followed by the GH of 1.005 BW? I'm curious if it's Instant Ocean in general or all SW mixes that bump GH so high.

Could I have a bad batch of Instant Ocean, should I switch to another brand?

I'm hoping this is not a big deal - Hoover the figure 8 looks great and seems totally fine. I probably have another month's worth of Instant Ocean left, though.

Thanks,

Eric

[Myaj]

Well, I think I have everything I need to do that test... I'll be back in a bit...

[Jayhawk]

Thanks Myaj - that would be great to see if it's all Instant Ocean or just my batch - I can't belive they really mean to buffer the GH up to that level.

Eric

[Myaj]

Well, I'm back, and after lots of digging around to find the test kits, my hydrometer, etc and finding lots of goodies (spare titanium heater, the missing half of my little mag float, etc) I somehow expect RTR to post anytime now and say "you goofballs, its SUPPOSED to do that!". Anyways, I had fun trying to get the salinity right, its been a while since I mixed up any brackish water.

My results were, tap water:

GH 13
KH 7-10 (starting turning color but not all the way at 7, changed completely at 10)
pH 7.5 but bouncing around



At 1.005:
GH 73, so no, its not just you
KH same
pH slightly higher, 7.6 or so but still bouncing



I'm interested to see what my tap water does after sitting out 24 hours now, since all my tanks have a higher pH reading than the tap (around 8.5 for most), and they give a good steady reading right away (using a digital pH pen) where the bucket of tap water didn't really seem to stay steady...

[Jayhawk]

Very, very interesting - were you using Instant Ocean?

So RTR, PP - is the GH really that high or is it simply that a FW GH test can't read BW?

Help us out here...and thanks for taking the time to replicate my experiment Myaj!

Eric

[Myaj]

Yes, I should have said that. Its a small box of instant ocean.

[Myaj]

Oh, and it it makes any difference...

It took me somewhere between a 1/4 cup and a 1/2 cup to get to 1.005 in a 2 gallon bucket. I put in a loosely scooped 1/4 cup into 2 gallons of water, got a reading of 1.002, added another, 1/4 cup but this one was packed a little tighter (not tightly packed), mixed, and that time it jumped up to 1.009! So then I had to dump some water, add fresh, etc...

I'm thinking the "packed" part is making a big difference as far as how much to use, sort of like how you don't pack flour when you measure it for baking, but you DO pack brown sugar... Which is it supposed to be with Instant Ocean? Maybe you have your scoop filled with more than PP does because its packed harder? I don't know.. All I care is that it reaches the right salinity hehe...

[Jayhawk]

I use tablespoons, and I realized last night that I have a 4 gallon bucket not a 5 gallon bucket. So when I use 4 tablespoons (non-rounded, but not perfectly level) I'm usually also dumping them into a bucket more likely filled to 3.5 or 3.75 gallons.

I still use less salt than PP, about on with what Pamela and now you reported.

And like you, I'm only concerned about the salinity being right (I double checked mine with a brewing hydrometer - the floating kind). Or at least that was my only concern until this GH thing came up.

I was at the LFS yesterday and looked to see if they had a specific GH test for SW, but I didn't see one. I may have to break down later this week when I have a car available to go to a Petco or Petsmart and see what other brands of Salt might be good and/or if there are specific SW GH tests.

Eric

[Pufferpunk]

This is true for me, no matter what brand of salt I use. This is the rough estimate I have been recommending on all 20 of the other websites & help out at & have never gotten a response that this estimate was too high. I wonder...

[RTR]

Robert is not replying because he has no BW or SW at the moment. I do have a spare box of unopened Instant Ocean Reef, but it is still sealed and in a sealed tub with desiccant. I will not convert it into a lump for a couple of tests.

Water of hydration can play havoc with some FW/SW testing, SW's chemistry plays games on you. Ca++ and Mg++ are both highly hydrated in solution, but I don't know if there are differnces in the FW/SW tests or if they are just compensated by the scale used, or if they are identical down the line.

But in any case, I would expect the alkalinity/KH to be well elevated at any specific gravity, and the same for GH/hardness. These two are big TDS boosters, second only to the NaCl itself.

Volume measurements and their instability with time have been beaten to death here and elsewhere. After the first opening of the box, tub, or bucket they are worthless, and even at the first use are really crude and notoriously unreliable. How many angels can dance on the head of a pin? How much/many tablespoons/cups of marine mix to use? Both questions have unknowable solutions.

I guestimate crudely and dissolve with strong circulation 24 hours, then I read and adjust salt content by adding more mix or more water dependent on the 24 hour reading, age 24 hours again and confirm that I am about where I want to be. But I am a lab fugitive, compulsive to the end. I believe hyrdometer readings, refractometer readings, TDS mesures, pH probes, etc. - if the instruments have been calibrated. I an incapable of believing/accepting any volume measure of highly hydroscopic material.

[Jayhawk]

Robert - I most certainly wouldn't expect you to open a sealed box just for a little test. I am curious about the testing, though, and curious about the high GH perhaps increasing the SG reading.

OK, one last digression on the SG issue which I am not overly concerned about. I know that refractometers are more acurate than swing arm hydrometers, but having used a floating hydrometer to also test SG (and testing the water at the 60 degrees the floating hydrometer is calibrated at) and getting the exact same reading most definitely says something about the SG - both instruments are reading the same. I think the odds of both being exactly off the exact same amount are very small - they're made by different manufactuers and likely made over 15 years apart. Also, I tend to trust my handy brewing hydrometer - when a recipe calls for a certain SG, I follow the recipe, and the SG is right on the money (I've used it since 1994). Additionally, it's obvious I don't rely just on volume measurements but use a hydrometer - measurements just give me a starting point.

OK, now the question is, is this high GH actually harmful to my figure 8?

PP - want to make up a small batch of BW at 1.005 with whatever brand of salt and measure GH with a FW test? I'm curious if other brands of salt lead to these high GH measurements...unless it's worthless to worry about the GH.

My key issue here is not wanting my fish not to be harmed by the funkily high GH.

Eric

[Pufferpunk]

Sure, as soon as I get more salt. I returned 2 hermit crabs this morning as a credit towards a bucket of salt but the owner wasn't there. I'll probably be picking up some later today. Good timing, I need to mix up some for a water change on my F8 tank.

[Jayhawk]

Thanks PP! You know, you could just test the GH from your Figure 8's tank. The GH is the main thing I'm interested in.

I just googled SW aquarium test kits, and none measure GH...which makes me wonder two things:

1) How do websites that list GH of brackish water come up with readings only of 20ish?

2) What is it that keeps GH from being a used test with SW kits.

I'm beginning to wonder if something in SW mix confounds GH tests.

I want to thank everyone for playing along so well...this is interesting stuff.

Eric

[Pufferpunk]

pH 8.2
GH off the chart. Didn't register even after 30 drops. (Test might be a little old, I never use it)
Ca2 220

[Jayhawk]

You've got a really high GH, too. I'd bet if you were willing to go another 30ish drops you would have gotten there (it almost overfilled my little tube - so half the tube was the test drops!).

I think I'm not going to worry about it or ever measure it again in my BW tank. I really appreciate your taking the time to test for me.

I really love my figure 8, and if everyone has GH's measuring high yet their fish are fine it's obviously either not a big deal or the tests don't work in BW.

The BW world is obviously the most neglected segment of fishkeeping - no BW tests, no BW medicines, few books on the subject, fewer BW fish in the LFSs, etc. Thank goodness for this board!

Eric