What would cause a major alk swing?

[moistowlette11]

New-ish to reefing. What would cause a major alk swing? Think 9.9-9.3 in one day. My corals closed up and got angry. Did a massive water change, and it has been slowly climbing back up. Now we are at 9.7. What would cause this to happen?

 

[BeejReef]

New-ish to reefing. What would cause a major alk swing? Think 9.9-9.3 in one day. My corals closed up and got angry. Did a massive water change, and it has been slowly climbing back up. Now we are at 9.7. What would cause this to happen?

That's not "Major," but great job noticing it and correcting.

Hard to say without some more detail on your tank. Generally, corals and coraline algae consuming alkalinity is a good thing and can appear to begin somewhat suddenly.

Can you describe your tank a little? How much water volume, how many corals and types (frags or colonies).
Are you dosing anything to maintain alkalinity? Do you do water changes?
Anything new with the tank lately? How old is your tank?

Also, even minor changes in salinity can appear to affect alkalinity. Do you run an ATO? Do you have a trusted refractometer?

 

[moistowlette11]

Okay, I'll answer the best I can

1. Tank is a biocube 32, started mid March with a proper cycle. I have all drags in the tank, no colonies.
1 x neon wall hammer
1 x black torch
1 x branching indo frammer
1 x candy cane
1 x anthellia
1 x xenia
1 x cyphastrea- having an issue, but suspect its STILL too much light, even though I put it in a low light area, so I moved it again.
1 x favia
1 x acan
1 x blastomussa
Various zoa/paly frags

3 x fish (clown, firefish, watchman goby)
2 x shrimp (cleaner and pistol)
3 x turbo snails (seriously good cleaners)
2 x small margarita snails (needed snails in a pinch, all the LFS had. Probably wouldn't buy again, but these are good.)
4-5 hermits, various sizes.
2 x emerald crabs

I run the LED lights that came with the tank. I have 16+ lbs of rock and some rubble in my filter and sand. I have chemipure in my sump and generous amounts of filter floss as well as a phosphate removing filter pad. I change this weekly but rinse it biweekly with RODI water. I use RODI water from my LFS.

I use IO salt, because it's what I will be able to get in a pinch should something happen (say, lost Amazon shipment). I change 5 gallons weekly or sometimes a little less than a week. I do not have an ATO, however my tank has a closed lid and I can monitor the levels on the side, I don't evaporate too much water because of the lid. I have had some algea problems that I have battled through (new tank uglies- diatoms, GHA, cyano, GHA again.) The turbo snails I got last week are really knocking down the GHA. I have a refractometer I bought on Amazon that I use, I keep salinity at 1.025. Temp between 77-79 depending on time of day.

My calc is usually 425-430 consistantly, mag 1230, nitrates consistantly 10. Phosphate has always been undetectable, which puzzles me. No ammonia of course.

Money is tight right now, but immediate improvements would be: intank media basket, skimmer, ato.

Help? Sorry for the word vomit.

 

[BeejReef]

Nothing in your description jumps off the page as a problem. Looks very solid to me.
A .5dkh swing in alkalinity isn't a real big shift. That's really within the testing error of most tests.

I'm no expert either, but I'd be surprised if that small a shift would seriously bother your corals. On the plus side, your tank is the right age now where you could expect to see some sustained consumption of calcium and alkalinity. Yaaaayyy, growth!

If your corals are really angry, you may have to consider other factors. If you can, post up a picture of some of the real unhappy ones. Maybe someone with a good eye will see something. Otherwise, it's a total guessing game.
My corals look a little sad when phosphate bottoms out, but not closed up. Some people keep a tighter range on their tank temp. You don't see a lot of people with near-sealed glass tops. Any RODI you're not making and testing yourself is a potential variable.... u see what I mean.. lol.

 

[Charlie’s Frags]

Have you used any products to treat aiptasia anemones?

 

[scott11106]

Nothing in your description jumps off the page as a problem. Looks very solid to me.
A .5dkh swing in alkalinity isn't a real big shift. That's really within the testing error of most tests.

I'm no expert either, but I'd be surprised if that small a shift would seriously bother your corals. On the plus side, your tank is the right age now where you could expect to see some sustained consumption of calcium and alkalinity. Yaaaayyy, growth!

If your corals are really angry, you may have to consider other factors. If you can, post up a picture of some of the real unhappy ones. Maybe someone with a good eye will see something. Otherwise, it's a total guessing game.
My corals look a little sad when phosphate bottoms out, but not closed up. Some people keep a tighter range on their tank temp. You don't see a lot of people with near-sealed glass tops. Any RODI you're not making and testing yourself is a potential variable.... u see what I mean.. lol.

i agree with this, you will have fluctuation and ALK in the 9's is good so i would not say that is the problem if corals are showing stress. hard to say without seeing it all but also would wonder if it could be time of day tested and there is fluctuation in testing. so you did a large water change and it increased your alk ? what is the alk of your fresh saltwater mix? also remember most salt mixes will raise certain parameters temporarily and then lower back down...not sure if that applies here

 

[ChiSox Rabbitfish]

My alk tested at 17 last night corals are doing great pretty sure it was a testing error

 

[moistowlette11]

Have you used any products to treat aiptasia anemones?

I have not, no aiptasia in my tank! Three or four weeks ago I did use chemiclean for cyano though, it didn't seem to anger anything.

 

[moistowlette11]

I will update with pics tonight when I get off work seriously glad to hear that's not a huge swing in alk. This is such a learning process.

 

[moistowlette11]

Here's a photo of what my angry frammer looks like, the recessed part was there prior to purchase/may have occurred during transport, and that was early may. It fluffed out and looked really happy for several weeks.

 

[lapin]

Did you do a water change in between measurements?
Maybe a new bucket of salt was opened?

 

[MnFish1]

New-ish to reefing. What would cause a major alk swing? Think 9.9-9.3 in one day. My corals closed up and got angry. Did a massive water change, and it has been slowly climbing back up. Now we are at 9.7. What would cause this to happen?

I would suggest that this is not a massive alk swing unless it happened very quickly (like in an hour) - and depending on the test - all 3 values might be within or close to the 'margin of error'. My guess would be (without knowing your other parameters) - is that something else caused the corals to be angry -But - water changes help angry corals for whatever cause. TO answer your question - adding something (a supplement) - or misdoing (if you dose) - or a problem with your dosing - or time of day (alk can fluctuate depending on time of day) - adding more coral that uses alk or a clam, etc.

But - I wouldn't worry about that value.

 

[SuncrestReef]

For those that aren’t aware, GFO can cause a drop in alkalinity. I discovered this last month after changing out my GFO media and then my Trident showed an immediate drop in alk by almost 0.5 dKH:



I’m not sure if this applies to the original poster’s situation, but wanted to point this out to anyone else who comes across this topic.