Low Alk, KH and pH

[Rcpilot]

My pH is consistantly down around 7.8. Alk is 2.29 and dKH is 6.4

My basic parameters are all completely fine. All ZERO ammonia, nitrite, nitrate, phosphates.

Calcium is off the chart--like 500+ No idea why.

I've dosed my pH and got it up to 8.2, but the very next day, it's back down to 7.8

I have noted that if I dose my Alk and get it up to more acceptable levels (4.00--4.70) then my pH will also remain within acceptable limits (8.0--8.4) Meaning, I can dose the Alk up and the pH will follow. I don't know why, but thats what is happening.

The tank is 30g. I started out with 40 pounds of crushed coral during my cycle. I cycled an empty tank with a deli shrimp. Took well over a month. THEN, I did some more reading and decided I wanted a finer sand bed. So, I took all 40 pounds of CC out and ran it through my kitchen blender--about a pound at a time. Got 85% of it ground up to fine particles. Reduced 100% of it to less than 1/8" size. THEN, I went out and bought 20 pounds of fine white reef sand. We're talking very fine--almost powder-- sand here. Total sand depth in the DT ranges from 3" too 5"

I have 61 pounds of live rock in the tank. 17 pounds of it was premium and well cured from a local reefer. 22 pounds was dry lace rock. And the remaining 22 pounds was "cured" from a LFS.

I am using a CPR HOB refugium with built in skimmer. It has 4.6g capacity and has a 5" DSB. I skim heavy and wet. I am using cheato in the refugium. I have had to thin the cheato twice in 5 months. The refugium lighting is 24w power compact. I run it at night--on a reverse light cycle. The flow through the refugium is 230GPH. The refugium light comes on at approx. 6pm.

The DT lighting is a T5 unit with 144w total. About 4.8w per gallon. I run the DT lights about 12hrs per day. They shut off at approx. 6:30pm

Flow in the tank is 760GPH. If you add the 230GPH from the refugium, it adds up to almost 1000GPH circulation in the tank. Roughly 33X turnover in this 30g tank.

I have:
1 diamond watchman goby 3"
1 6-line wrasse 2.5"
1 ocellarous clwon 1.5"
1 purple mushroom 2"
1 colony green stripe mushrooms 10 heads 1.5" each
9 colonies zoas 200 heads total
1 colony brown button polyps 6 heads
1 colony yellow polyps 12 heads

I do weekly water changes. 5g every Sunday. I am using a REALLY nice 6-stage RO/DI unit. I am using Oceanic salt. The tank has been set up for about 5 months. I keep salinity around 1.024--1.025

If I've left something out--please let me know. I've tried to provide you with ALL the information about the tank.

 

[lcstorc]

Good job on the details.
Here are a couple of good links for you.
Chemistry and the Aquarium
Chemistry and the Aquarium
Reef Chemistry Calculator

 

[bluespotjawfish]

We ought to have a low pH club!

Low pH: Causes and Cures by Randy Holmes-Farley - Reefkeeping.com

Reef Aquarium Water Parameters by Randy Holmes-Farley - Reefkeeping.com

Chemistry and the Aquarium

The best articles I have found yet in helping you understand what to do for low pH. I would make sure and check your magnesium if you are having a problem keeping the alk up. The higher alk will help with the low pH. Just make sure your calcium is also in the high range (which it is), and that your magnesium is in the normal range.

Good luck.

 

[Rcpilot]

Okay:
In the first article, it gives Zones that indicate where you're at. I'm in Zone 3 with low Alk.

BUT--then it says that if your Alk is high, then your Calcium is typically LOW. This is NOT my situation. My Calcium is off the chart. WAY HIGH.

The articles says that dosing Alk to bring it UP will also bring the Calcium DOWN. This sounds GREAT to me. Kill 2 birds with one stone.

I used the flash player calculator and it says I will need almost 68ml of Alk buffer to do the job. Remember in my original post, I stated that rasing my Alk leads to an increase in pH as well? I'm thinking 69ml of Alk buffer is going to push my pH up to about 13.

What I'd like to know is:
WHY is my Alk so far out? What is it that is causing my Alk to be so low? I know what will happen if I can raise it. But WHY is it such a problem? If I can find out what is causing it--then maybe I can cure THAT instead of adding chemicals to my tank.

Thanks so much for the links. That was very educational and it has helped. I just don't know how to fix it yet.

 

[Rcpilot]

Okay, I'm about to start dosing my Alk. SLOOOOWLY.

I need to monitor my pH and Alk while I do this. I realize this will take several days to adjust and that all these adjustments should be done slowly.

At what point can I start testing my pH and Alk after dosing? Can I dose--wait 30 minutes and test? Or do I need to wait 24hrs after dosing?

 

[mps9506]

I might have missed it, but I didn't see what test kits you are using.
Certain brands are known to test way off, and if you are not dosing calcium chloride then there is no reason your calcium should be that high.
Start with the test kits first then go from there

 

[Rcpilot]

I'm using Salifert test kits for these important tests. I use API for the basics like ammonia, nitrite and nitrate.

From the links bluespotjawfish supplied, it seams dissolved co2 has an effect on pH. If there is too much co2, then pH can be effected and run on the low side. Simple answer--lower the co2 in the tank. I have no way to test that.

Here is a short video of my surface aeration. I also have sloshing from the return box of the refugium. I don't know how much oxygen is added from the skimmer, but it's gotta help.

 

[DaveK]

My pH is consistantly down around 7.8. Alk is 2.29 and dKH is 6.4

My basic parameters are all completely fine. All ZERO ammonia, nitrite, nitrate, phosphates.

Calcium is off the chart--like 500+ No idea why.

I've dosed my pH and got it up to 8.2, but the very next day, it's back down to 7.8

I have noted that if I dose my Alk and get it up to more acceptable levels (4.00--4.70) then my pH will also remain within acceptable limits (8.0--8.4) Meaning, I can dose the Alk up and the pH will follow. ...

My tank on this a a bit different.

In my opinion, you have a major imbalance between calcium, pH and alkalinity.

I believe this has been caused by trying do "dose your way out". In other words, all the additives are at least partially responsible for the problem.

What I would do is mix up a fresh batch of SW, let it circulate for 24 hours, and then test it for calcium, pH and alkalinity. When doing the tests make sure the SG is at 1.025, and if possible use a refractometer to test this. A small difference is SG can result in a big difference in the tests.

If the new SW doesn't give normal readings for calcium, pH and alkalinity, then you need a new brand of salt. Switch brands and try again, until you get one that works.

Once the new SW is giving good readings, make large partial water changes, until things stabilize in the tank. This could take a very large number of partial water changes, because some of the additives used may have precipitated out. With the water changes, some may reenter solution. Expect this to be a long drawn out process.

During this time, do not attempt to adjust calcium, pH or alkalinity by using any additives. Let the water changes do the work.

Once you get the system stable, your problem will be resolved.

 

[bluespotjawfish]

Did you test magnesium? Start there, otherwise you are not going to get anything corrected. Most salt mixes are low in magnesium. My little 29 was over 500 without any supplementing of calcium. I got it back in check with waterchanges (using water that had correctly balanced alk, calc, and mag). I wouldn't personally try to correct the problem in a small tank like that with supplements. Add supplements to the water change water, recheck the alk, calc, mag, and pH the next day to make sure it is where you want it. As for why, look closely at the part about elevated CO2 in the following article. Unless my windows are open all day, I have to increase my alk (and that means increasing the calc too) to keep the pH up. If they aren't balanced it is usually because of low magnesium.

Low pH: Causes and Cures by Randy Holmes-Farley - Reefkeeping.com

 

[Rcpilot]

I don't have a magnesium test.

As for the comments about "dosing my way out" I'm not offended--just don't think you understand the whole picture. I'm NOT the only person using supplements or buffers in my tank. I actually have been VERY reluctant to dose my tank for a long time. I have suffered with this problem for the last 2 months while my water parameters are whacked out. This problem did NOT occur because I was willy nilly dosing over the last 5 months. It occured naturally and I tried--to no avail--to fix it a couple times with dosing. Do not assume that I've created this problem myself by dosing the tank continuously over a long period. That is not the case. I've dosed my pH twice in the last 2 weeks and I've dosed my Alk once.

I'm going to buy a magnesium and oxygen test from Salifert. I like their tests and trust them.

From what I've been reading (thanks for the links) it seams the corals will use the Alk/bicarbonate in the tank for their growth. Is this correct? While I do not have any "corals" yet--if it's true that corals DO take up and use the Alk, how do people with lots of these animals maintain Alk levels? Do they not dose the tank in some fashion?

 

[Woodstock]

When you say you "dose for PH", what are you using? PH buffers are either a sodium carbonate or a sodium bicarbonate. Both increaase the alkalinity. PH buffers = alkalinity supplements.

Oceanic salt = VERY HIGH in calcium and CHRONICALLY LOW in alkalinity. I suggest you test your newly made salt water PRIOR to using it for a water change and supplement it for alkalinity. Better yet... switch salt brands to CoralLife. No matter what salt brand you use, ALWAYS test it prior to using it in a water change and supplement as needed. I test for calcium, alkalinity and magnesium.

Lot of things 'use' alkalinity. Acids (dirty tank/filters/overfeeding,etc) use it up; growing corals developing an exoskeleton; growing coralline algae; hamelidia algae; or anything else that grows a calcium base.

I think your #1 issue is using a salt mix low in alkalinity.

 

[Rcpilot]

That kinda sucks because I bought the 160g bucket of Oceanic salt mix about 2 months ago and I got a LOT of it left.

I really have no way to clean my DSB. 95% of it is covered with rocks, so I can't really vacuum the top layer. Thats why I bought the goby and 2 nessarious snails. I also recently found a hitchhiker serpent star in my sand bed. Thats about as clean as it's gonna get. I'd hate to think my tank is dirty. :bugout: That would make me feel awful. I try so hard to take good care of my fishies and inverts. I want them to be healthy and happy.

I may buy another bucket of salt and start mixing it with my Oceanic salt. You recommended the Coralife salt. I'll give that a whirl.
Is this it?
Saltwater Aquariums: Coralife Marine Salt

I'm taking a water sample to the LFS tomorrow and have them test all my water. See if my tests are accurate.

I'm mixing up a fresh batch of water tonight and will test it with everything I got. I'm going to order some more Salifert tests from the 2 Docs this week.

 

[Rcpilot]

When you say you "dose for PH", what are you using? PH buffers are either a sodium carbonate or a sodium bicarbonate. Both increaase the alkalinity. PH buffers = alkalinity supplements.

I was using SeaChem Reef buffer.

Lot of things 'use' alkalinity. Acids (dirty tank/filters/overfeeding,etc) use it up; growing corals developing an exoskeleton; growing coralline algae; hamelidia algae; or anything else that grows a calcium base.

I don't have any corals with exoskeleton right now, so that can't be it. I don't really have any "filters". Just a refugium and an awesome skimmer. I admit to overfeeding. I use a turkey bastor to spot feed brine to polyps. Not all of it gets trapped by their tentacles. I figure the rest of it settles on the bottom of the DT or refugium and gets eaten by bristleworms, snails and crabs. I can certainly cut back on the feeding.

I think your #1 issue is using a salt mix low in alkalinity.

That would be an EASY fix. I can only pray that is the problem.

 

[Woodstock]

Do not throw it out. You can use the oceanic just be add an alkalinity booster to it before use.
I currently use only Tropic Marin Pro Reef on my reef tank and in my hospital tank I use either corallife or Instant ocean because it is much cheaper and I perform lots of large water changes.

Don't worry about vacuuming the dsb. Stirring upthe top 1/2" of it prior to a water change helps to remove ditritus.

 

[Woodstock]

"Reef Buffer" and "Reef Builder" are both alkalinity supplements.

 

[Rcpilot]

The Seachem Reef Buffer I used says that it will raise Alk and pH.

It says that they make another product called Reef Builder. It says Reef Builder will raise Alk when pH is not a problem. So, I gather it will raise the Alk and not the pH. I do not have this product. I used Reef Buffer.

I'll take some water to the LFS tomorrow and have them test it. See if my tests are accurate.

 

[hma]

You adjust a too small KH value best by the addition of natriumhydrogencarbonat (soda). You get that in the supermarket, in the pharmacy or in LFS. In your aquarium an shift of Ca Ions took place, each further dosage of Calzium reduced automatically the pH and KH. Natriumhydrogencarbonat adjusts this ion shift.

BTW take a look on my HP (Balling)and (Kalkwasser vs CA reactor)

 

[Woodstock]

An Improved Do-it-Yourself Two-Part Calcium and Alkalinity Supplement System by Randy Holmes-Farley - Reefkeeping.com

Let me try to explain.... there are two types of alkalinity supplements; sodium carbonate and sodium BIcarbonate.
Sodium carbonate is the EXACT same thing as sodium bicarbonate BUT it does not have co2 in it.
Sodium bicarbonate is the exact same thing as sodium carbonate but it has a lot of co2 in it.
If you bake the sodium bicarbonate in the oven and drive out the co2, voila~ you have sodium carbonate.

Co2 reduces PH.

Sufficient gas exchange at the water's surface is important so that the water lets off excess co2 and absorbs oxygen; this will help keep your PH up.
It is also important to "air out" your house (open a few windows or doors) frequently to flush out the high co2 that naturally builds up in your home.

baking soda (arm&hammer) = sodium bicarbonate (may initially lower PH)
BAKED baking soda (arm&hammer) = sodium carbonate (raises PH)

Low co2, sufficient alkalinity, and low organics will keep the PH up.

 

[Rcpilot]

Somebody else suggested it is my CC. Actually, it's not the CC that is causing the problem. Rather, it's a LACK of aragonite sand. I only have 20 pounds of aragonite sand in my DSB. The other 40 pounds of DSB is the crushed coral that I sent through the kitchen blender to bust it up into smaller pieces. So, that 20 pounds of aragonite is all mixed up and some of it is probably all the way down on the bottom of the DSB.

It's been suggested that I replace the DSB completely with 100% aragonite sand. Supposedly, that is a better buffer over a long timeframe. The CC has lost it's ability to buffer--thats the theory.

What do you guys/gals think of that theory?

 

[Woodstock]

Many reefs are barebottom.
While it's true that crushed coral can trap ditritus and may attribute to a low PH by creating acids, having crushed coral or the lack of it or any other sand bed is not required to keep alkalinity & calcium balanced.