ALK Swing when PH maintain within range. Please help!!

[duyhuynh]

I have been paying attention at my tank closely everyday since the day i set it up (about 8 months ago). I look at signs of unusual activities from my fishes, LPS, SPS to any crawling creatures in my tank. My set up is completely automated with Apex controller, ATO, and dosing.

For the past 2 months, i notice that some of my SPS polyps are not opened, and they show signs of discoloration, bleaching from the tips. Some have died, and some are on the verge. My PH is falling from 8.02 minimum to maximum 8.25, and the average is 8.12. I would say PH range is ok. If PH is somewhat stable, Alk should be stable too. I checked my ALK last night, and i was surprised that it was around 7.5. The last time i checked it (1 week ago), it was at 8-9. Calcium is also in range from 400-420.

Every time i change water (5gal/week) i add 1 tsp of Mg and 2 tsp of calcium in the 5 gal bucket and mix it with red sea salt.

Some of my SPSs are fine like the EFFLO and gomezi. Other LSP are doing fine.
Why are my SPSs dying? VuChu (Irvine) stopped by my house last night and inspected the tank visually (Thanks Vu). He agreed that my SPSs are not happy for some reasons.

I need to mention about my RODI water too. My TDS level has been increasing to 180 which is unacceptable, and i am changing the cartridges. I have been using water with high TDS level for some time.

Can anyone give some advises?

 

[Arkayology]

7.5 dkh is really not that low. I usually keep my tank around 8.0dkh and I know others who keep their tanks around 7.2-7.5 dkh without a problem. It is about the stability. You want to keep your dkh as stable as possible. From your post is appears as if you are doing water changes to supplement your tank's consumption of calcium and calcium carbonate? It may be time for you to invest in a doser. Just a thought.

Have you checked some pests?

 

[duyhuynh]

7.5 dkh is really not that low. I usually keep my tank around 8.0dkh and I know others who keep their tanks around 7.2-7.5 dkh without a problem. It is about the stability. You want to keep your dkh as stable as possible. From your post is appears as if you are doing water changes to supplement your tank's consumption of calcium and calcium carbonate? It may be time for you to invest in a doser. Just a thought.

Have you checked some pests?

Thanks for the comment.

I forgot to mention that i do run my dosing pump 35ml for part A, 35ml for part B, and 150 ml for Kalkwasser.

I dont see any pests beside a few aiptasia.

 

[duyhuynh]

Nobody has any clue?

 

[vuqchu]

Well, we know for sure it's the swings. I think partly because of the extra stuff you add to your new water when you do your water change. The IO salt you use is already pretty close to you tank's parameters that it's a nonevent when you are changing the amount you currently do. But when you put more stuff in it, then it makes it more noticeably different. Plus, the TDS reading on your new water is crazy high at 200+. That tells me your filter may not even be filtering any of the stuff the city water district in putting in when they filter the water for public use. That's just a couple things I noticed off the bat.

 

[duyhuynh]

Well, we know for sure it's the swings. I think partly because of the extra stuff you add to your new water when you do your water change. The IO salt you use is already pretty close to you tank's parameters that it's a nonevent when you are changing the amount you currently do. But when you put more stuff in it, then it makes it more noticeably different. Plus, the TDS reading on your new water is crazy high at 200+. That tells me your filter may not even be filtering any of the stuff the city water district in putting in when they filter the water for public use. That's just a couple things I noticed off the bat.

The TDS level is quite high in Stanton, Ca comparing with Irvine, Ca. Tap water in Stanton, Ca has TDS around 400. Even when i change all the cartridges from the RODI, TDS is hard to get to 0. Should i buy the RO water instead

 

[vuqchu]

You should be able to get zero if you change out all your cartridges with new ones. Don't know about you, but I would be kicking myself big time if I were to lose hundreds if not thousands worth of stuff on something that would have cost around $30-40 to replace. That's IF that was the main cause. Not preaching or anything, but I wouldn't even fill up the tank in the first place if the water is bad to start out with. Just sayin

 

[jefathome]

I'm in Missoin Viejo and we have 500 TDS water and even w/ brand new cartridges I can only get down to about 5 TDS.

 

[ChefZilla]

The alk swing from 7.5 to 9 isn't good but I don't think it would kill your sps... make them unhappy yes... I think your biggest issue is your RO water. You should never let it get above 8 IMO. Why don't you piggy back another membrane or di resin cartridge? Having the 2nd membrane will give you less waste water as well .

 

[duyhuynh]

I'm in Missoin Viejo and we have 500 TDS water and even w/ brand new cartridges I can only get down to about 5 TDS.

After changing the cartridges, TDS is down to 4.
I cant believe that Mission Viejo TDS is that high. What is the city doing with the water? Irvine has only 250 TDS i believe.

 

[duyhuynh]

The alk swing from 7.5 to 9 isn't good but I don't think it would kill your sps... make them unhappy yes... I think your biggest issue is your RO water. You should never let it get above 8 IMO. Why don't you piggy back another membrane or di resin cartridge? Having the 2nd membrane will give you less waste water as well .

I just changed all the cartridges, and TDS is only 4 right now. I will add another membrane of DI resin cartridge to lower the TDS
Thanks

 

[keepLearning]

There is a few fish store selling RO/DI water (TDS near 0) for $0.25-$0.50 a gallon. If you water is that bad, it might be cheaper to buy the RO/DI water from a LFS.

My faucet water TDS is <230. I let the RO runs for about 1 gallon then the TDS drops to 3-4 before I hook up the DI canister. I have not changed my DI for over 1.5 years. I don't use much like 20 gallons a week most so it makes sense for me!

I just changed all the cartridges, and TDS is only 4 right now. I will add another membrane of DI resin cartridge to lower the TDS
Thanks

 

[billyzbear]

We could use some more info.
What kind of lights? Flow? Size of tank? ...
Do you have a chloramine filter, for ro water?
Red Sea salt is pretty high in alk and ca. already not sure why you are adding to it before water change. I would rather you adjust your tank water after water change.
With my own tank I have noticed sps becoming dull over time. I add red sea colors now and it has helped some, polp extension is good. I also feed sps red sea reef energy.
But sps color is still muted. I'm going to up light intensity, I have leds and t5's. I'm going to pull some leds and add more t5's. Back when I had all t5's things looked better.

You also have not mentioned phospate. Do you test it? With what? I find you need to have a really good tester so I have my LFS test it for me. If it's really low your sps will look dull if it's too high you'll get algae growth.
How do the other coral look? LPS and softies? What fish do you have? Pickers?