View Full Version : SeaChem Reef Salt - alk testing
Hello and thank you for the wonderful support system.
I have been using SeaChem Reef Salt since starting my new system 55G cube about 6 months ago.
I am a little perplexed at my KH results. I use an API test kit. I seem to be continuously getting 6 - 7 dKH levels.
Someone mentioned to me the borate in the SC Reefsalt and suggested to either change salt brand or test kit.
SeaChem test kits are not always readily available in Australia and if found, they are priced very high (even on comparison of the US sites where I find the costing is far more comparible to other quality grands). The API kit is new ... while not overly pricey I hate throwing money away (I have done enough of this in this hobby).
Are you able to give some guidance as to the comparison of what the API kit is measuring to how the borate in the salt may be interfering with the result?
I'd love to see a better range of your test kits readily available here but until then, this is what I have to work with. I need to know whether I need to raise my KH or not ... and if so, how much.
Tech Support JS
Thanks for posting. Depending on your test kit, it may be testing for either 'total alkalinity' or 'carbonate hardness (KH).' Alkalinity is a term often used synonymously with KH, but they are not the same. Alkalinity is a measure of your total acid binding ions, including bicarbonate, carbonate, phosphate, borates, iodates, silicates (and the list goes on). KH is a measure of only your carbonates and bicarbonates. Because of this, you may have a high alkalinity, but a low KH (however you cannot have a high KH and low alkalinity). Since Reef Salt contains borate in addition to carbonates and bicarbonates, you will see an elevated alkalinity, but not necessarily KH. Our ReefStatus: Magnesium and Alkalinity test kit, if you can get your hands on it, allows you to distinguish between total alkalinity, carbonate alkalinity, and borate alkalinity. Unfortunately, other test kits may claim to test for 'Alkalinity' but in reality are only testing KH, since the term is so widely used in place of KH. Rest assured your Reef Salt will contain a superior amount of alkalinity for buffering. I hope this clears up any confusion you may have!
Okay that does clear things up a little - I think... :(
The test kit I use is testing for KH and not GH (which I see now refers to General hardness). The brand is API and I find these easily accessible in my area. Sorry to say but the SeaChem kits are still harder to find.
If all else fails, until I locate a SeaChem kit, would I be better off getting my hands on the GH / KH kit rather than just relying on the KH alone? I am pretty sure API make one that measures both GH and KH.
I had no idea that there was a difference --- always learning something new.
Andrea - South Australia
Tech Support AN
Thanks for the post! KH, like JS said is referring to your carbonate hardness (carbonates/bicarbonates) and GH (general hardness) is actually referring to the calcium and magnesium content of your water. These two (KH/GH) are totally separate entities. There are so many ions in saltwater, your test kit would be totally overwhelmed. Testing GH is mainly for freshwater environments. I think that you are ok to rely on the API KH test kit, until you can get a Seachem kit that measures total alkalinity. I can assure you that the Reef Salt is far superior to anything else in supplying a sound and stable alkalinity for buffering your water. I hope this was helpful and please let us know if you have any further questions!
Okay ... again, much clearer and many thanks for taking the time to respond.
I do have one other question.
I often worry that due to shipping / storage, my salt tub may have settled out and I may not be getting a consistent mix with each batch. Not being the strongest female, I do struggle mixing these big heavy buckets when new.
So I had this idea I wanted to run by you.
Would it be feasible to pre-mix the entire contents of a new bucket (600L) into a 200L food grade drum with a powerhead for circulation. I could then pull off the salt water concentrate and dilute with RO/DI water as needed...
This I would hope would give me a more consistent mix each time.
What are your thoughts?
Tech Support JS
I wouldn't recommend that. You will definitely run into more problems doing that that you would if there were settling in the bucket (i.e. suppressed pH, algae growth, etc). Moreover, settling in the salt bucket does not typically occur, and the parameters should be generally uniform throughout each mix. Thanks for the post and have a great day!
I recently switched to SeaChem Reef Salt, and I've also noticed low readings with my API KH test kit (<8) compared to what I used to get with IO Reef Crystals (10). I'm glad to know about the reason for the discrepancy, but what would be a good target KH range using this salt and this test kit? With the Reef Crystals, I supplemented a couple of times a week (testing first, of course!) with Reef Carbonate to keep the tank KH at 10. Now I'm not sure if the target value should still be 10 with this salt mix.
Tech Support EH
Though natural sea water only has an alkalinity of about 2.5meq/L, it is important to keep this higher in an aquarium system for pH stabilization and to keep other parameters where they should be. We recommend targeting an alkalinity of 4-6 meq/L, or between 12-16 dKH, no matter what salt and test kit you are using.
That's a much higher recommendation for dKH than I've seen before. I thought I was shooting for 8-12. (I'm keeping mainly corallimorphs, inverts, and a fish, but I'd like to shift the balance in the tank to less hair algae and more coralline algae.)
But anyway, please see the post above from TechSupportJS. The question here is whether the usual conversion from meq/L alkalinity to dKH holds with this salt. The implication was that KH might read low but in reality alkalinity might be fine. Assurance was given that Reef Salt has a superior alkalinity content for buffering, in spite of low dKH readings. So now you are telling me that I should bring the dKH WAY up from what it is when the salt is mixed out of the bag? Can you please explain these conflicting recommendations?
Tech Support LK
If your kit is measuring in meq/L, it is measuring total alkalinity. If it is measuring in dKH, it is most likely measuring for carbonates. If you assume that all of your alkalinity is is made up of carbonates, then the conversion is applicable. If not, then it won't be. If your dKH is at 8 using Reef Salt, then most likely, your total alkalinity is somewhere around 3.9meq/L (which would convert to 11 dKH which is perfectly acceptable). It is up to you whether or not you want to adjust up further and this will be dependent upon the bio-load of your aquarium and how much your pH/alkalinty shifts between water changes. I apologize for the suggestion by Tech Support EH, she meant to say 4-6 meq/L including your borate alkalinity. A dKH of 8-10 is just fine.