Help with alkalinity dosing - how much should I be dosing?

[Zer0]

Long story short, I believe all I need to dose is alkalinity, but I have no experience with dosing aside from manually dosing phyto and aminos. I bought an automatic dosing pump, and I would like to set it up.

I wanted to see how much resources my tank used up over a period of two weeks, so I did a 50% water change, did baseline tests for Mag/Cal/Alk, waited two weeks and then redid the tests. Magnesium and Calcium didn't really get used up too much, which I guess is normal considering I only have a handful of SPS, the rest are LPS and soft coral. The one thing that did see the most significant usage was alkalinity. At the beginning my alkalinity was around 7.2 and when I tested everything today, it came back as 5.1. I was originally going to start dosing Kalk+2, but now I'm not sure that's what I need. I think all I need to dose is alkalinity.

I have a small tank, a 10G cube, which has I would say a decent amount of coral in it. Goniopora and zoanthids are definitely the majority, but I do have 6-7 SPS.

And if you're wondering why bother dosing at all on such a small tank when I could probably accomplish the same thing with water changes, that's true, but if I can just use an automatic doser and then do water changes like once a month instead of once a week or bi-weekly, I think that would be ideal. It would also give nitrates and phosphates a chance to increase a bit since I'm on the very low end for nutrient levels, like, near zero.

I don't think my tank uses up enough alkalinity for me to be able to get daily results to break it down easier, which is why I gave it two weeks. So now I'm hoping I can get some advice from the experts to finalize what I need to dose and how often.

Thank you for any and all assistance! If I missed any necessary information just let me know!

 

[T-J]

Using the information you provided, it looks like your alk is dropping .15 a day (2.1 alk drop / 14 days). So for 10 gallons, using BRS soda ash, you would need to add about 1 ml a day to keep it stable. Again, that's using your numbers over 2 weeks.

When I set up my dosing schedule, I tested every 24 hours for a few days to get my daily consumption.

 

[Oldreefer44]

Agree with T-J with one additional thing. You don't mention what test kit you are using. I have found that there is a lot of variability between test kits and therefore it is a good idea to verify your results before basing your dosing regimen on what could be a false baseline. So if you have a local LFS that could check for you then for you then great. If not then I would either buy a different brand of test kit to compare with or even send in for an ICP test

 

[T-J]

Agree with T-J with one additional thing. You don't mention what test kit you are using. I have found that there is a lot of variability between test kits and therefore it is a good idea to verify your results before basing your dosing regimen on what could be a false baseline. So if you have a local LFS that could check for you then for you then great. If not then I would either buy a different brand of test kit to compare with or even send in for an ICP test

I generally agree with this as well. I use a Hannah checker for my alk. I've compared it to my Salifert kit and they are usually within .2 of each other. Honestly, stability is really the key. If your test kit says 8, and it's really 8.5, it not a big deal.
FYI, I'm currently keeping my alk at 9. I may raise it, but for the past several months, 9 has been my target.

 

[Zer0]

Thank you everyone! I’m using Salifert test kits for everything except nitrate/phosphate which are Hanna. I suppose I could see if a lfs can test my water so I can compare their results against mine, that seems like a sound idea and gives me an excuse to get another frag or two lol.

 

[Chris Spaulding]

Also with a small tank and 1 dowsing pump check into Tropic Marin All-for Reef

 

[Zer0]

Also with a small tank and 1 dowsing pump check into Tropic Marin All-for Reef

Yeah AFR was the first thing I looked into but apparently the powder isn’t available in the U.S. yet and I didn’t think the liquid was as good a deal as the powder available in the EU. It might be something I look in to in the future as the reef matures and eats up more resources, but I think all I need currently is to keep my alkalinity stable. At least that’s just what I can tell from the test kits, as far as how the coral look, they still look as good as they did two weeks ago lol.

 

[blasterman]

ZerO, I keep small tanks like you do and grow them out to be pretty kick butt tanks. I also like to keep things simple, reliable and cheap.

Do not use an automatic dosing pump. Tank is too small.

It is very common for a small tank to blow through a lot of alk but not calcium. Unless you have one of my freak show SPS jungles going on you can almost certainly get away with water changes for calcium. However alk can deplete faster than water changes and you should never increase water changes to compensate for alk. You are dumping money down the drain .

Alk is stupid easy to manually dose. Use a box of baking soda and the online reef calculator. You typically dose like a quarter teaspoon or so a night, but the reef calculator will tell you exactly how much.

One problem: that 7.2 starter value doesn't seem right. The only salt mix i know that mixes alk that low is maybe Tropic Marine Pro. In any respect, I would target a dKH of about 9 for a small tank and simply use a box of baking soda to keep it there. Yes, it is that simple.

 

[Zer0]

ZerO, I keep small tanks like you do and grow them out to be pretty kick butt tanks. I also like to keep things simple, reliable and cheap.

Do not use an automatic dosing pump. Tank is too small.

It is very common for a small tank to blow through a lot of alk but not calcium. Unless you have one of my freak show SPS jungles going on you can almost certainly get away with water changes for calcium. However alk can deplete faster than water changes and you should never increase water changes to compensate for alk. You are dumping money down the drain .

Alk is stupid easy to manually dose. Use a box of baking soda and the online reef calculator. You typically dose like a quarter teaspoon or so a night, but the reef calculator will tell you exactly how much.

One problem: that 7.2 starter value doesn't seem right. The only salt mix i know that mixes alk that low is maybe Tropic Marine Pro. In any respect, I would target a dKH of about 9 for a small tank and simply use a box of baking soda to keep it there. Yes, it is that simple.

I'm using IO reef crystals, and I mix the water to 1.025. I thought the alk was low as well, but I've tested it a few times and I have two different alk test kits. I mean, same brand of test kit, both Salifert, but they're two separate kits.

 

[arking_mark]

Using the information you provided, it looks like your alk is dropping .15 a day (2.1 alk drop / 14 days). So for 10 gallons, using BRS soda ash, you would need to add about 1 ml a day to keep it stable. Again, that's using your numbers over 2 weeks.

When I set up my dosing schedule, I tested every 24 hours for a few days to get my daily consumption.

A 2.1 dKH Alk drop would have a roughly corresponding 14ppm Ca drop. This Ca drop would fall in most tests error range and hence why many think they only need Alk. APEX Trident has a 15ppm precision.

http://reefkeeping.com/issues/2004-12/rhf/index.htm

 

[Rmckoy]

I'm using IO reef crystals, and I mix the water to 1.025. I thought the alk was low as well, but I've tested it a few times and I have two different alk test kits. I mean, same brand of test kit, both Salifert, but they're two separate kits.

Io generally has higher alk ….

the one thing that comes to my mind , have you confirmed the salinity is in fact 1.025?

 

[MaxTremors]

Long story short, I believe all I need to dose is alkalinity, but I have no experience with dosing aside from manually dosing phyto and aminos. I bought an automatic dosing pump, and I would like to set it up.

I wanted to see how much resources my tank used up over a period of two weeks, so I did a 50% water change, did baseline tests for Mag/Cal/Alk, waited two weeks and then redid the tests. Magnesium and Calcium didn't really get used up too much, which I guess is normal considering I only have a handful of SPS, the rest are LPS and soft coral. The one thing that did see the most significant usage was alkalinity. At the beginning my alkalinity was around 7.2 and when I tested everything today, it came back as 5.1. I was originally going to start dosing Kalk+2, but now I'm not sure that's what I need. I think all I need to dose is alkalinity.

I have a small tank, a 10G cube, which has I would say a decent amount of coral in it. Goniopora and zoanthids are definitely the majority, but I do have 6-7 SPS.

And if you're wondering why bother dosing at all on such a small tank when I could probably accomplish the same thing with water changes, that's true, but if I can just use an automatic doser and then do water changes like once a month instead of once a week or bi-weekly, I think that would be ideal. It would also give nitrates and phosphates a chance to increase a bit since I'm on the very low end for nutrient levels, like, near zero.

I don't think my tank uses up enough alkalinity for me to be able to get daily results to break it down easier, which is why I gave it two weeks. So now I'm hoping I can get some advice from the experts to finalize what I need to dose and how often.

Thank you for any and all assistance! If I missed any necessary information just let me know!

I would start dosing a good quality balanced two part. Even if it seems like your calcium may not be going down much, you still want to dose it with the two part, and base your dosing off of your alkalinity readings.

So get a reef dosing calculator on the App Store, input the brand of two part your using, the total tank volume (actual volume not tank size), and then enter where you ended up (5.1) and where you’d like to be (I’d shoot for 8dkh), and it will tell you how much you need to dose over a two week period. So then divide that by 14 and it will give you the daily amount to dose.

You want to slowly bring your alk up to where you want it (so maybe dose double what your daily value will be until you get to your target, and then go down to the daily dose).

It’s important that you dose the calcium with it. Nearly all corals and organisms that use alkalinity and calcium use it at the same ratio, so even if it seems like your calcium isn’t going down by much, it’s still going down some, dosing the same amount of part 1 and part 2 should keep it balanced. For instance on my tank, i dose around 1ml of both parts per day, for my tank volume and consumption that equals to around 0.15dkh and a little less than 1ppm of calcium). You want to be sure to keep an eye on your levels as you begin dosing (test daily for a week or two) and then test once or twice a week to monitor your consumption (as your corals grow, they’ll consume more).

 

[Rmckoy]

Here is the calculator I use .

easy to use and offers a choice of many different products http://reef.diesyst.com/chemcalc/chemcalc.html

 

[rkoshin1]

ZerO, I keep small tanks like you do and grow them out to be pretty kick butt tanks. I also like to keep things simple, reliable and cheap.

Do not use an automatic dosing pump. Tank is too small.

It is very common for a small tank to blow through a lot of alk but not calcium. Unless you have one of my freak show SPS jungles going on you can almost certainly get away with water changes for calcium. However alk can deplete faster than water changes and you should never increase water changes to compensate for alk. You are dumping money down the drain .

Alk is stupid easy to manually dose. Use a box of baking soda and the online reef calculator. You typically dose like a quarter teaspoon or so a night, but the reef calculator will tell you exactly how much.

One problem: that 7.2 starter value doesn't seem right. The only salt mix i know that mixes alk that low is maybe Tropic Marine Pro. In any respect, I would target a dKH of about 9 for a small tank and simply use a box of baking soda to keep it there. Yes, it is that simple.

Great f****** info right there. I have a redsea nano (20g) and that sums it up perfectly, and yes baking soda works perfectly if you are trying to save $ from and not buy alk products.

 

[Dkeller_nc]

Something definitely seems a bit off. Unless IO has made a substantial change to their formulation recently, Reef Crystals typically has an alkalinity of about 12dKH if mixed to a specific gravity of 1.026. There are several ways that one could observe an alk value that's substantially lower than that. One's batch-to-batch variation and/or settling in the container. I personally think these factors are fairly rare - IO has been making artificial salt mix longer than almost anyone else, and I'd guess their QC is pretty tight. And even if they don't take steps to control the particle size of the various inorganic compounds that go into a salt mix, it would still take a good deal of vibration during shipping and handling to actually stratify the components enough so that the aquarist would see a large amount of alk value variation between one batch of ASW that he/she mixed up and a subsequent one out of the same bucket.

The other two likely factors that would affect the alkalinity of a batch of ASW are inaccurate specific gravity measurements, and performing alk tests on "aged" ASW. Inaccurate specific gravity measurements are pretty common, especially if performed by refractometry. Yes, there's some issues with the quality/calibration of instruments from the factory, especially if they're the "look through" type with mechanical temperature compensation via bimetal strip. But another source of error is the aquarist misinterpreting the scales in the instrument and/or calibrating the device with suspect refractometry standards.

The issue with "aged" ASW is that these mixes are fundamentally chemically unstable as a homogeneous solution. The carbonate/bicarbonate and calcium levels in these salt mixes allows the calcium to slowly combine with the carbonate/bicarbonate and precipitate out as insoluble calcium carbonate. That will, of course, lower the measured alkalinity as the ASW sets around in the bucket. And the higher the temperature, the faster this reaction will occur. Generally (and it varies greatly from salt mix to salt mix), you're good for several hours to a day or so without a testable drop in alkalinity. In my experience, unheated HW Weigandt reefer salt mix maintains the same apparent alkalinity for a week or two at about 65 deg F. If I heat the mix to tank temp of 78 deg F, the alkalinity falls by about 2 dKH over the course of about 4 days. I experienced similar results when I used Reef Crystals before I switched the HW Weigandt.

One aspect of this that I'll mention - there's nothing inherently wrong with allowing freshly mixed ASW to "age" to get an intentional drop in alkalinity. In fact, I used to employ just that strategy with Reef Crystals, as the typical 12 dKH that I was obtained by testing new ASW (with Salifert's alk test, btw) was higher than I wanted for larger water changes.

 

[Zer0]

I mix my salt to 1.025 @ 77F and typically I use a digital Hanna salinity tester, which I cross check with a Tropic Marin precision hydrometer, so I think my salinity is probably correct. I’m not really sure what to tell you. I know how to use the Salifert alk test kits and I have two of them just to be sure. I never get anywhere near 9, let alone 12 dkh. I always roll the bucket of salt a few times before use as well.

 

[T-J]

I also use a Hanna salinity tester. Make sure you buy a box of the calibration packets and calibrate it monthly.

 

[Zer0]

I also use a Hanna salinity tester. Make sure you buy a box of the calibration packets and calibrate it monthly.

Yep I got them, I calibrate it every two weeks because normally I do a water change every Sunday morning so I use it pretty often.

 

[Dkeller_nc]

If you're confident about the specific gravity measurements, you're measuring the new ASW right after it's fully mixed and clear, and you've high confidence with the alkalinity measurement, the only other explanation that I can think of is that Instant Ocean has changed the target alkalinity of Reef Crystals downward. I haven't used RC in the last 3 or 4 years after I switched to HW Weigandt, so I'd definitely not have any basis for commenting on what freshly mixed RC "should be" as far as alk is concerned.

One other possibility - ASW mixes are fairly stable in powder form as long as the humidity and temperature are kept in reasonable ranges. However, if the moisture content of the salt mix goes up substantially from storage in high humidity and/or high temperature conditions, the carbonates and calcium in the mix can combine to form insoluble calcium carbonate. That would result in a lower alkalinity measurement when the salt is mixed up to the correct specific gravity.

In general, but not always, one can make an assessment about the storage conditions at the vendor based on the free-flowing nature of the mix, because as calcium and carbonates in the mix combine to form insoluble calcium carbonate, the salt mix tends to clump. In extreme cases the whole bucket will have to be broken apart with a hammer.