Issue with KH after using new unrinsed purigen

[Noahspapa]

I have a 10 gallon tank, which had completed a six week dark start to cycle, and was then about 4 weeks planted with eleocharis and blyxa, using an oase biomaster thermo (1) 350, a twinstar S series light, an inline CO2 diffuser, and a PH controller. The degassed ph value was 7.2 and the ph controller was set to 5.8. The tank was running this way for several weeks with the drop checker lime green towards yellow. Fish and plant health were good. Some minor algae problems. KH was somewhere between 1 & 2 (blue with one drop, yellow with two drops). KH was 6. Ammonia & nitrites tested weekly at zero. I was doing a weekly pre filter cleaning and decided to check in the trays. Saw the purigen looked kinda brown. I had additional bags of new purigen put together for a new tank. I started things up and ran it. No worries. Later in the day I notices the drop checker as blue. Thought that was weird. Next day same thing. PH showed 5.3 on ph controller. Tested ph with Hanna handheld meter. 5.3. Recalibrated probe. Still 5.3. Thought through what had changed. Took the purigen out. Restarted. Watched ph very slowly ramp back up to 5.8. Took the bag of purigen nd put it in a bucket of RODI water. After 48 hours ph was 3.8. Been doing 50% water changes every there’s day. No significant change. Tested kh using 50ml sample. Zero! I believe whatever blew out of the bag of purigen is sucking all the carbonates out of the water. I decided to start adding KH using a conditioner to get KH back to a level that results in a ph of 7.2. As I add KH conditioner ph jumps up so I try and do it slowly. And over time the carbonates get sucked back out but now I seem to be able to hold at KH of 0.5.

Any thoughts on how to get the tanks water chemistry back to a level where I can inject co2 again?

BTW I contacted seachem. They asked me to write it up and submit. I did. They eventually got back to me and told me purigen does not impact ph and that they recommend using as directed going forward. Idea being I didn’t rinse as directed which is true. They are not providing any additional info..

 

[Rob23]

What are you using as a substrate?

 

[Noahspapa]

What are you using as a substrate?

UNS controbase and UNS controsoil.

 

[Rob23]

I've read that aquasoil can lower kH over time. I wonder if the UNS substrates also have this effect.

 

[Dennis Wong]

Its not the purigen its the aquasoil.
Its by design, and tanks run fine with low pH generally, unless you are keeping livestock that requires alkaline water (then you should avoid aquasoils).

kh-gh-tds /is-low-ph-in-tanks-due-to-aquasoils-softwater-a-concern" data-host="www.2hraquarist.com" data-pending="false">

Are bacteria affected due to low pH/KH in aquasoil tanks?

Does the low pH caused by CO2 injection or aquasoil affect livestock or bacteria in the planted aquarium? Should I use buffers to raise the pH?

www.2hraquarist.com

 

[Noahspapa]

I've read that aquasoil can lower kH over time. I wonder if the UNS substrates also have this effect.

Its not the purigen its the aquasoil.
Its by design, and tanks run fine with low pH generally, unless you are keeping livestock that requires alkaline water (then you should avoid aquasoils).

Are bacteria affected due to low pH/KH in aquasoil tanks?

Does the low pH caused by CO2 injection or aquasoil affect livestock or bacteria in the planted aquarium? Should I use buffers to raise the pH?

www.2hraquarist.com

Hello and thank you for the response. I understand what you are sharing and appreciate it. The 2hraquarist website is an incredible resource! In the case of this tank, the tank had been operating at a near steady-state, with this aquasoil and hardscape, with a degassed ph of 7.2, brought down to a ph of 5.8 which made the drop checker lime green and it was operating like this for over a month until the maintenance session where I swapped in this unrinsed bag of purigen. The ph then quickly (hours not days) lowered to 5.3 with no CO2. I’m pointing out and am concerned about the rapid change not so much a concern that the ph is low. I also think (admittedly unqualified) it’s odd that putting a bag of this unrinsed purigen in a bucket of RO water brings the ph down to 3.8 with no aquasoil. And most importantly I’m trying to figure out how to go forward with this tank as far as operating with CO2 once again. At a new degass value for ph of 5.8 I’d need to run at a ph of 4.8 to achieve the one degree drop?

 

[gnatster]

Just tossing this out there…. When was the last time you cleaned and calibrated the pH probe.

 

[Noahspapa]

Just tossing this out there…. When was the last time you cleaned and calibrated the pH probe.

Thank you for your input. I had calibrated it a month earlier and then recalibrated it that day once this happened and there was no change. I also checked with a Hanna handheld unit and had the same result - so, two independent measurements.

 

[Noahspapa]

Thank you for your input. I had calibrated it a month earlier and then recalibrated it that day once this happened and there was no change. I also checked with a Hanna handheld unit and had the same result - so, two independent measurements.

Just tossing this out there…. When was the last time you cleaned and calibrated the pH probe.

Adding - I’m a beginner aquascaper, plant keeper, fish keeper but retired from a 40 year career in test equipment for the defense electronics industry. So I do have some background with that.

 

[Koan]

Okay that's freakish It sounds like you've eliminated the other variables besides the Purigen dust.

Seachem advertises the resin ingredient as "..macroreticular. It has microscopic pores that increase its usable surface area to many times that of a purely spherical resin.."

So could a cloud of micro-particles of this resin bind up the carbonate that's in your system? Apparently

I think your core question was really whether it is still safe to inject CO2 even though you seem to have lost all your KH and your pH is already low. Injecting CO2 with low or even zero KH is actually fine for plants contrary to popular wisdom. Here's a review of why:

gh-tds /kh-explained" data-host="www.2hraquarist.com" data-pending="false">

What is a good level for KH in a planted aquarium ?

Does KH matter in a planted aquarium ? What is a good level of KH to have? Is it necessary to buffer the tank from pH crashes? This page explores the role that carbonate hardness (KH) plays and how to raise and lower the KH level in an planted tank.

www.2hraquarist.com

What you do have to watch out for is if you have sensitive livestock, especially snails or shrimp. Livestock with calcium carbonate shells will have difficulty maintaining their shells with increased acidity as that will tend to dissolve them. You do want to make sure you still have adequate calcium in your GH as well.

Watch your fish carefully as an abrupt change in KH can certainly affect their osmoregulation as well. If they seem distressed you may need to relocate them temporarily.

The good news is, there's a limited quantity of this dust. Worst case scenario you add some bags of crushed oyster shell chicken grit and relocate your livestock for a week or two until your tank settles back down.

 

[Noahspapa]

Okay that's freakish It sounds like you've eliminated the other variables besides the Purigen dust.

Seachem advertises the resin ingredient as "..macroreticular. It has microscopic pores that increase its usable surface area to many times that of a purely spherical resin.."

So could a cloud of micro-particles of this resin bind up the carbonate that's in your system? Apparently

I think your core question is was really whether it is still safe to inject CO2 even though you seem to have lost all your KH and your pH is already low. Injecting CO2 with low or even zero KH is actually fine for plants contrary to popular wisdom. Here's a review of why:

What is a good level for KH in a planted aquarium ?

Does KH matter in a planted aquarium ? What is a good level of KH to have? Is it necessary to buffer the tank from pH crashes? This page explores the role that carbonate hardness (KH) plays and how to raise and lower the KH level in an planted tank.

www.2hraquarist.com

What you do have to watch out for is if you have sensitive livestock, especially snails or shrimp. Livestock with calcium carbonate shells will have difficulty maintaining their shells with increased acidity as that will tend to dissolve them. You do want to make sure you still have adequate calcium in your GH as well.

Watch your fish carefully as an abrupt change in KH can certainly affect their osmoregulation as well. If they seem distressed you may need to relocate them temporarily.

The good news is, there's a limited quantity of this dust. Worst case scenario you add some bags of crushed oyster shell chicken grit and relocate your livestock for a week or two until your tank settles back down.

Thank you very much for this.

 

[Koan]

You bet! That's what we're here for

 

[Count Krunk]

Personally, I would remove the purigen. Not needed. With an Oase 350 on a 10g just the sponges inside the filter have TONS of surface area. Esp for a 10g tank.

 

[Dennis Wong]

Hello and thank you for the response. I understand what you are sharing and appreciate it. The 2hraquarist website is an incredible resource! In the case of this tank, the tank had been operating at a near steady-state, with this aquasoil and hardscape, with a degassed ph of 7.2, brought down to a ph of 5.8 which made the drop checker lime green and it was operating like this for over a month until the maintenance session where I swapped in this unrinsed bag of purigen. The ph then quickly (hours not days) lowered to 5.3 with no CO2. I’m pointing out and am concerned about the rapid change not so much a concern that the ph is low. I also think (admittedly unqualified) it’s odd that putting a bag of this unrinsed purigen in a bucket of RO water brings the ph down to 3.8 with no aquasoil. And most importantly I’m trying to figure out how to go forward with this tank as far as operating with CO2 once again. At a new degass value for ph of 5.8 I’d need to run at a ph of 4.8 to achieve the one degree drop?

Hmm this is interesting. As mentioned, you could remove the purigen for now since your filtration is probably more than adequate to give crystal clear water by itself.

 

[Kwyet]

It makes me wonder if it’s actually Purigen. Maybe something was mis-packaged.

 

[Noahspapa]

Thank you for your responses. I removed the purigen that day and it’s been out for a week or maybe two? I removed my endlers from the tank today as someone in the thread suggested. I lost a few over the past week or so which is uncharacteristic for my tanks. I personally think they were harmed the day I put the unrinsed purigen in. I started injecting co2 again this afternoon. I set the ph controller to 5.8 as it used to be and will check on things in the AM. Pm plants (eleocharis, blyxa) are thriving. They need trimming.

Personally I was disappointed seachem didn’t want me to send them one of the bags to test it. I offered. I worked at Northrop Grumman and once notified our QA dept would have issued a quality bulletin and began an investigation but this is not that. I discarded the purigen and have an order in to seven ports for their product. I’ll move on now but I truly believe the tank was impacted.

Thanks again for all the inputs. A major thing I truly love about this hobby is the willingness for collaboration and assisting we beginners.

 

[Koan]

I worked at Northrop Grumman and once notified our QA dept would have issued a quality bulletin and began an investigation

Yea, Seachem does not exactly have the best reputation on that score