Alkalinity rising?

Randy Holmes-Farley · Apr 20, 2020

I forget what you are using for top off, but have you tested it for alkalinity?

if it is the rock, you may need to regularly add an alkalinity reducer until it stabilizes.

eshtog · Apr 20, 2020

Randy Holmes-Farley said:
I forget what you are using for top off, but have you tested it for alkalinity?

if it is the rock, you may need to regularly add an alkalinity reducer until it stabilizes.

Randy, I really appreciate you chiming in! What alkalinity reducer do you recommend in a reef tank?

Yes, tested my RODI water and it changed color on the first drop so no Alkalinity in my top off water :( Looking back at my order history the rock that is in my tank is BRS MarcoRocks Reef Saver Aquarium Dry Live Rock. I'm stumped and don't know what to do. The rock has been in the tank for over 2 years and the same frustrating cycle of rising alkalinity continues.

Randy Holmes-Farley · Apr 21, 2020

Whichever of the two you use below, it must be done slowly because they lower pH a lot.

Best if you use them on new salt water for water changes, and drop the alk very low in them, then aerate to drive off the CO2.

But you can also add them very slowly to the reef tank itself.

The two choices are sodium bisulfate (such as seachem acid buffer or online; it is a solid) or muriatic acid (a liquid that is more dangerous if you spill it on yourself or your clothes).

sgrosenb · Apr 21, 2020

eshtog said:
Randy, I really appreciate you chiming in! What alkalinity reducer do you recommend in a reef tank?

Yes, tested my RODI water and it changed color on the first drop so no Alkalinity in my top off water :( Looking back at my order history the rock that is in my tank is BRS MarcoRocks Reef Saver Aquarium Dry Live Rock. I'm stumped and don't know what to do. The rock has been in the tank for over 2 years and the same frustrating cycle of rising alkalinity continues.

@eshtog I use Seachem Acid Buffer as Randy mentioned to lower my Alk. I have a 150g display and I drop 1/2 TSP in when my pH has peaked for the day. It lowers my pH by about 0.1. So, like Randy said, a little bit goes a long way and can lower pH quickly so be careful.

hobbyreefer · Apr 28, 2020

My tank is ~6 months old. It was started with man made "real reef" rock. I also used carib sea sand. My tank experienced a MAJOR Dino and Hair Algae outbreak. Every surface in the tank was covered in long stringy algae. I beat the issue with a large UV sterilizer. I also was dosing Microbacter 7 and Vibrant. Once the tank cleaned up I started seeing a rise in DKH of about .2 DKH per day. My DKH was rising but I was not dosing anything. I was not dosing 2 part, Vibrant, Nitrates, etc. Nothing. I would do a weekly water change and see my DKH go down. I would test daily and see a consistent rise in DKH. My RODI top off water was 0 TDS and 0 DKH...

I ended up removing all of my Carib Sea sand in a single swoop. I've now gone 2 weeks without my DKH rising at all. It is actually drops a bit each day as expected.

This is just an anecdotal case and I'm not saying the sand was the issue. Obviously there are thousands of successful reef tanks with Carib Sea sand. I just didn't know what else to try.. Just wanted to share my experience as I know others have struggled with DKH rising.

My tank is about 160 gallons water volume
100 pounds of Real Reef Rock
2.5 bags of Carib Sea Arag Alive "Reef Sand" (1.5 inches or so on the the bottom)
I'm growing Corraline everywhere which should have lowered the DKH without dosing - I was stumped...

Randy Holmes-Farley · Apr 28, 2020

hobbyreefer said:
My tank is ~6 months old. It was started with man made "real reef" rock. I also used carib sea sand. My tank experienced a MAJOR Dino and Hair Algae outbreak. Every surface in the tank was covered in long stringy algae. I beat the issue with a large UV sterilizer. I also was dosing Microbacter 7 and Vibrant. Once the tank cleaned up I started seeing a rise in DKH of about .2 DKH per day. My DKH was rising but I was not dosing anything. I was not dosing 2 part, Vibrant, Nitrates, etc. Nothing. I would do a weekly water change and see my DKH go down. I would test daily and see a consistent rise in DKH. My RODI top off water was 0 TDS and 0 DKH...

I ended up removing all of my Carib Sea sand in a single swoop. I've now gone 2 weeks without my DKH rising at all. It is actually drops a bit each day as expected.

This is just an anecdotal case and I'm not saying the sand was the issue. Obviously there are thousands of successful reef tanks with Carib Sea sand. I just didn't know what else to try.. Just wanted to share my experience as I know others have struggled with DKH rising.

My tank is about 160 gallons water volume
100 pounds of Real Reef Rock
2.5 bags of Carib Sea Arag Alive "Reef Sand" (1.5 inches or so on the the bottom)
I'm growing Corraline everywhere which should have lowered the DKH without dosing - I was stumped...

It might be the real reef rock not being adequately cured.

sgrosenb · Apr 28, 2020

hobbyreefer said:
My tank is ~6 months old. It was started with man made "real reef" rock. I also used carib sea sand. My tank experienced a MAJOR Dino and Hair Algae outbreak. Every surface in the tank was covered in long stringy algae. I beat the issue with a large UV sterilizer. I also was dosing Microbacter 7 and Vibrant. Once the tank cleaned up I started seeing a rise in DKH of about .2 DKH per day. My DKH was rising but I was not dosing anything. I was not dosing 2 part, Vibrant, Nitrates, etc. Nothing. I would do a weekly water change and see my DKH go down. I would test daily and see a consistent rise in DKH. My RODI top off water was 0 TDS and 0 DKH...

I ended up removing all of my Carib Sea sand in a single swoop. I've now gone 2 weeks without my DKH rising at all. It is actually drops a bit each day as expected.

This is just an anecdotal case and I'm not saying the sand was the issue. Obviously there are thousands of successful reef tanks with Carib Sea sand. I just didn't know what else to try.. Just wanted to share my experience as I know others have struggled with DKH rising.

My tank is about 160 gallons water volume
100 pounds of Real Reef Rock
2.5 bags of Carib Sea Arag Alive "Reef Sand" (1.5 inches or so on the the bottom)
I'm growing Corraline everywhere which should have lowered the DKH without dosing - I was stumped...

@hobbyreefer thanks for the info. Just curious - do you remember rinsing your sand prior to putting it in the tank? If so, any idea if it was with RODI water or tap water? I have absolutely no idea if this would make a difference (I'll let Randy tell me I'm way off here) but maybe it's possible that rinsing with tap water could have compromised the sand?

I'm thinking about taking my sand out as a test as well. I ahve roughly a 0.1-0.2DKH daily rise as well still. I have started with Reef Saver dry rock and Tropic Eden Mesoflakes, which are also aragonite.

hobbyreefer · Apr 28, 2020

I did not rinse the sand. Just dumped it in. All of my previous tanks have been bare bottom so I wanted to try something different. I regretted it immediately. The sand probably wasn't the issue, but it is interesting that the DKH stopped going up the moment I removed all sand... I'm now 16 days without a DKH rise!

sgrosenb · Apr 28, 2020

hobbyreefer said:
I did not rinse the sand. Just dumped it in. All of my previous tanks have been bare bottom so I wanted to try something different. I regretted it immediately. The sand probably wasn't the issue, but it is interesting that the DKH stopped going up the moment I removed all sand... I'm now 16 days without a DKH rise!

I gotta believe that's a possible culprit. I'm tempted to remove mine and see what happens. But it's obviously odd that not many others who use sand (which is obviously many, many people) don't have the same issue.

Randy Holmes-Farley · Apr 28, 2020

Sand and live rock can slowly dissolve deep down in it where degradation of organics can lower the pH to the point where calcium carbonate dissolved. People with tanks for years sometimes have to add to the sand, probably for this reason.

eshtog · Apr 29, 2020

hobbyreefer said:
My tank is ~6 months old. It was started with man made "real reef" rock. I also used carib sea sand. My tank experienced a MAJOR Dino and Hair Algae outbreak. Every surface in the tank was covered in long stringy algae. I beat the issue with a large UV sterilizer. I also was dosing Microbacter 7 and Vibrant. Once the tank cleaned up I started seeing a rise in DKH of about .2 DKH per day. My DKH was rising but I was not dosing anything. I was not dosing 2 part, Vibrant, Nitrates, etc. Nothing. I would do a weekly water change and see my DKH go down. I would test daily and see a consistent rise in DKH. My RODI top off water was 0 TDS and 0 DKH...

I ended up removing all of my Carib Sea sand in a single swoop. I've now gone 2 weeks without my DKH rising at all. It is actually drops a bit each day as expected.

This is just an anecdotal case and I'm not saying the sand was the issue. Obviously there are thousands of successful reef tanks with Carib Sea sand. I just didn't know what else to try.. Just wanted to share my experience as I know others have struggled with DKH rising.

My tank is about 160 gallons water volume
100 pounds of Real Reef Rock
2.5 bags of Carib Sea Arag Alive "Reef Sand" (1.5 inches or so on the the bottom)
I'm growing Corraline everywhere which should have lowered the DKH without dosing - I was stumped...

Thank you so much for sharing! At this point I really don't have any other options and will remove my sand in the next day or two. I'll report back with the results.

sgrosenb · Apr 29, 2020

eshtog said:
Thank you so much for sharing! At this point I really don't have any other options and will remove my sand in the next day or two. I'll report back with the results.

@eshtog I'll be really interested to hear how it turns out for you!

eshtog · May 4, 2020

@hobbyreefer @sgrosenb I was going to wait a bit more to post this, but after months of Alkalinity rising with no solution I couldn't wait! On April 29th in the evening I took out 85% of my sand and the rest the next day. As you can see by the chart my Alkalinity has stayed stable and has even declined from the time I took out the sand! The huge drop in Alkalinity is because the day I took out the sand I did a big water change using water that I added muriatic acid to.

I will keep this thread updated as more time goes by, but initial results are very promising. Now the question is why would the sand be the cause of rising Alkalinity?

hobbyreefer · May 4, 2020

That is very interesting. I've now gone another 6 days without DKH rising (about 3 weeks total). I'm actually dosing soda ash daily now to keep stable. I'm sure it's in my head, but my sticks appear to have much better PE since removing the sand. I also added 2 additional MP40s so the flow could be helping too.

Randy Holmes-Farley · May 4, 2020

eshtog said:
@hobbyreefer @sgrosenb I was going to wait a bit more to post this, but after months of Alkalinity rising with no solution I couldn't wait! On April 29th in the evening I took out 85% of my sand and the rest the next day. As you can see by the chart my Alkalinity has stayed stable and has even declined from the time I took out the sand! The huge drop in Alkalinity is because the day I took out the sand I did a big water change using water that I added muriatic acid to.

I will keep this thread updated as more time goes by, but initial results are very promising. Now the question is why would the sand be the cause of rising Alkalinity?

Where did you get the sand?

I wonder if it was contaminated.

Randy Holmes-Farley · May 4, 2020

I also assume that fine particles of the sand were definitely not getting up into the water column and into an alk test? Solids in an alk test will dissolve and look like excess alkalinity.

hobbyreefer · May 4, 2020

My tank looked cloudy for weeks. I assumed I was just going through a bacteria bloom, but when I added filter socks the cloudiness went away. I wonder if my sand was blowing around and getting into the water column and influencing the alkalinity test? Is this what you are saying? Sounds plausible. However, I used a very common sand Carib Sea Reef and I had two MP40s on a 5' tank. This has to be a common setup. I would think a ton of other people would have similar results if this is what was happening.

I purchased my sand from my local LFS and it was new and sealed in the bag. I don't recall the expiration date. Maybe they sold me older sand that was somehow contaminated? Either way, removing all of the sand appears to have instantly resolved the issue for my specific case.

Randy Holmes-Farley · May 4, 2020

hobbyreefer said:
My tank looked cloudy for weeks. I assumed I was just going through a bacteria bloom, but when I added filter socks the cloudiness went away. I wonder if my sand was blowing around and getting into the water column and influencing the alkalinity test? Is this what you are saying? Sounds plausible. However, I used a very common sand Carib Sea Reef and I had two MP40s on a 5' tank. This has to be a common setup. I would think a ton of other people would have similar results if this is what was happening.

I purchased my sand from my local LFS and it was new and sealed in the bag. I don't recall the expiration date. Maybe they sold me older sand that was somehow contaminated? Either way, removing all of the sand appears to have instantly resolved the issue for my specific case.

If it was fines of sand, that would definitely boost the apparent alk, if not the real alk.

Good to be rid of it anyway, since it might make knowing the real alkalinity hard.

eshtog · May 4, 2020

Randy Holmes-Farley said:
If it was fines of sand, that would definitely boost the apparent alk, if not the real alk.

Good to be rid of it anyway, since it might make knowing the real alkalinity hard.

This is the sand I used

20 lb. Special Grade Arag-Alive! Reef Sand

Natural Perfection with CaribSea's Special Grade Reef Sand Contains Live Bacteria to Assist with a Faster Cycle High Surface Area for Bacteria Ready to Use - No Rinsing CaribSea's Special Grade Arag-Alive! Reef Sand offers a natural look and the perfect particle size for maintaining a...

www.bulkreefsupply.com