Rising Alkalinity

[RichardinMa]

What could cause alkalinity to rise over time even though nothing is being added to the system? When freshly mixed, my alk is at 9 but has increased to 12-13. I do not dose anything but do run Chemipure Ultra and Purigen.

[tmz]

Perhaps the 'freshly mixed" salt contains some undissolved alk. What salt mix? How much salt is dosed? How are you measuring it?

Something else in the tank could be dissolving if ph is low.

Neither purigen nor chemipiure contain alkalinity.

[disc1]

What are you using for top off water. If you're using treated tap water, then it is possible that the tap water contains some alkalinity.

If you're using good pure RODI water then that's not it.

[Randy Holmes-Farley]

Alk does not rise without additions some way.

Did you bleach the Purigen from a previous use? Bleach has a lot of alkalinity.

[RichardinMa]

Alk does not rise without additions some way.

Did you bleach the Purigen from a previous use? Bleach has a lot of alkalinity.

This is why I am finding this so frustrating. The purigen is new and has not been bleached. When you mentioned that, however, I had another thought. I typically wash my micron sleeves in the washing machine with bleach, run them through an extra rinse, then run them through another cycle with plain water and yet another extra rinse. I then replaced them into the sump the following day. Even though they usually had a slight scent of bleach I had read that others have used them like that without issues. Perhaps this is why?

This is the system that I have been having SPS issues with (different thread)and I suspected it was due to either alk issues or the zero nutrients in there. Regarding my top-off water, it is still currently tap but that runs about 4 in alk and my other tanks that I use it in are not having this problem. I am having to dose to raise the alk in those. I am really starting to suspect the bleach as I am pretty sure that the last time I had an alk reading of 12-13 (Monday)was a couple days after washing the bags. I retested today (Saturday) and it was at 10. I'm not sure why it would fall so quickly though. My high reading was verified by a friend's test kit (different brand) as well.

I use Reef Crystals and my alk on new water is usually around 9-10 on that.

I appreciate the responses and hope I get to the bottom of this soon.

[disc1]

Regarding my top-off water, it is still currently tap but that runs about 4 in alk

That's probably a lot more alkalinity than the bleach could possibly add. Your top off water should be a zero for alk. Otherwise it works out to a daily addition of alkalinity to the tank. If that is more than the tank uses up, then your alkalinity rises.

[Steve Wright2]

could it be something as simple as failing to tighten the top down on one of the test kit reagents, making the liquid more concentrated and thus taking more drops to change colour?

[Randy Holmes-Farley]

I agree that the rinse cycle will remove the bleach to the point where it couldn't be the alk cause. :)

[Randy Holmes-Farley]

could it be something as simple as failing to tighten the top down on one of the test kit reagents, making the liquid more concentrated and thus taking more drops to change colour?

The only problem with that idea is it would go the other way, taking less if the acid titrant is more concentrated. :)

[RichardinMa]

Perhaps it is the source water that is the problem but I did not think that adding water with alk at 4 would raise it that much. Additionally, the same source water is used for my other 5 systems and they do not have this problem. Of course, they are more heavily stocked so perhaps this is why. The system is on an ATO now and perhaps the smaller amounts of water being added now are not enough to give that spike as I saw in the past. I will monitor it more closely now and see what the trend is.

I was planning on adding a Kold Steril filtration unit as this has a few advantages that appeal to me- the main one being zero waste water. The system was suggested to me by Oceanus Inland Reef and I have been very impressed with her systems and coral. Michele swears by the system. Any opinions on whether this will be okay? I use my tap on other plants and animals that are very sensitive to minerals without ill effect so there is not a great deal of impurities in my water to begin with. My town does not even typically chlorinate.

[RichardinMa]

could it be something as simple as failing to tighten the top down on one of the test kit reagents, making the liquid more concentrated and thus taking more drops to change colour?

The high alk was also verified by a friend's test kit which is a different brand than mine.

[disc1]

I did not think that adding water with alk at 4 would raise it that much.

That's about half of your target level. Can you imagine what would happen to salinity if you were topping off with saltwater at 1.013? The same thing will happen here.

[Randy Holmes-Farley]

Perhaps it is the source water that is the problem but I did not think that adding water with alk at 4 would raise it that much. Additionally, the same source water is used for my other 5 systems and they do not have this problem. Of course, they are more heavily stocked so perhaps this is why. The system is on an ATO now and perhaps the smaller amounts of water being added now are not enough to give that spike as I saw in the past. I will monitor it more closely now and see what the trend is.
.

If the demand is lower than what is supplied by that water, then the alk will rise. :)

I'm not a fan of the kold sterile. There are many threads on it so you might want to check those out.

Here's one:

http://www.reefcentral.com/forums/showthread.php?t=1562818

[Habib]

Did something die, or is it cycling, or some new rock added?

Many organics can mimic alkalinity.

[RichardinMa]

Did something die, or is it cycling, or some new rock added?

Many organics can mimic alkalinity.

Nothing died, no cycles, etc... I am fairly certain now that it must be a result of the tap water. Before I switched to an ato I would top off once or twice a day. It is a 120 gal system and I would go through about 2-3 gal per day. I think that dumping that much tap in at once must have skewed the chemistry more than the ato does at a trickle. I will be testing again tomorrow to see what the alk is but my gut is telling me this is what it is. The fact that I do not have these problem in my other systems does make sense as they do not go through nearly as much water (covered tanks) and the one that is open is far more heavily stocked than the big system is.

I appreciate the threads on the Kold Steril. After reading through them I am leaning more toward the RO/DI. The alk, PO4 and SI and the main things i was looking to pull out of the water and that system does not seem to do much for those.

[Randy Holmes-Farley]

:thumbsup:

Good luck. :)