Parameters rising without dosing

[MONTANTK]

I’ve been having trouble keeping parameters stable while using the AWC feature with the Dos so I decided to take it offline. Ever since then, my alk and magnesium have been rising rapidly despite the fact that I have stopped dosing. How is this possible??

 

[Timfish]

Biofilms, endoliths, sponges and "other stuff" all are manipulating the levels in a system and may be contributing by either directly dissolving calcerous substrates or creating pH gardients that dissolve calcerous substrates adding to the levels in the water column. Additionally, if something disrupts corals feeding or photobiology their lack of consumption may help levels increase.

 

[Randy Holmes-Farley Verified Community Expert]

What are the values?

Assuming you are not adding it somehow, the magnesium is not likely rising but is test error or a salinity increase.

Alk can slowly rise if there is very little demand and the calcium carbonate sand is slowly dissolving deep down where the pH is low.

 

[MONTANTK]

What are the values?

Assuming you are not adding it somehow, the magnesium is not likely rising but is test error or a salinity increase.

Alk can slowly rise if there is very little demand and the calcium carbonate sand is slowly dissolving deep down where the pH is low.

Since October 7th Alk has increased from 7.9 to 8.7 and Mg has increased from 1380 to 1470. Another change I made was adding some filter socks that I had cleaned with bleach. I noticed most of my corals look healthy but I have a Goni and a zoa frag that don’t look very happy. I’m wondering if it has something to do with the bleach maybe not being rinsed all the way

 

[MONTANTK]

Biofilms, endoliths, sponges and "other stuff" all are manipulating the levels in a system and may be contributing by either directly dissolving calcerous substrates or creating pH gardients that dissolve calcerous substrates adding to the levels in the water column. Additionally, if something disrupts corals feeding or photobiology their lack of consumption may help levels increase.

Hmmm okay. I don’t have any sponges or floss in the tank but I did add a filter sock that had been soaked in bleach and rinsed. Wondering if that had any impact. Other than that, I can think of anything else that would be contributing to the issue

 

[Randy Holmes-Farley Verified Community Expert]

Assuming you are holding salinity constant (are you?) the magnesium rise is test error. VERY common, up and down. There is no in tank source for that much magnesium without shooting alkalinity through the roof.

If the sg is 1.025 and it rises to 1.026, magnesium at 1380 ppm will rise to 1435 ppm. So tight control of salinity is necessary if you intend to focus on smallish magnesium changes.

 

[MONTANTK]

Assuming you are holding salinity constant (are you?) the magnesium rise is test error. VERY common, up and down. There is no in tank source for that much magnesium without shooting alkalinity through the roof.

If the sg is 1.025 and it rises to 1.026, magnesium at 1380 ppm will rise to 1435 ppm. So tight control of salinity is necessary if you intend to focus on smallish magnesium changes.

Hmmm okay that would make sense. I have been topping off by hand for a while and I had a lot of water displacement the past few days. Salinity is probably fluctuating between 1.026 and 1.027. How would you explain the rise in Alkalinity?

 

[Mr Cypher]

What is your P04 at? I had a similar issue recently alk went from a stable 12 and started climbing when I posted some one told me that high phosphate can lead to the corals not taking up nutrients and and cause stuff to rise

 

[MONTANTK]

What is your P04 at? I had a similar issue recently alk went from a stable 12 and started climbing when I posted some one told me that high phosphate can lead to the corals not taking up nutrients and and cause stuff to rise

I will let you know shortly. It has been stable at .04 but I haven’t tested it in a week. I plan on testing it shortly

 

[Randy Holmes-Farley Verified Community Expert]

Hmmm okay that would make sense. I have been topping off by hand for a while and I had a lot of water displacement the past few days. Salinity is probably fluctuating between 1.026 and 1.027. How would you explain the rise in Alkalinity?

Could be any or a combination of:

1. Additions that you do not recognize as adding alk
2. Declining or dosing nitrate (adds alk)
3. Slow dissolution of sand
4. Salinity changes (1.025 to 1.026 boosts alk from, say 8.0 to 8.3 dKH)
5. Test error (most kits have substntial uncertainty with each measurement

Note on the last one, even the Hanna alkalinity checker (HI772) has an uncertainty of +/-0.3 dKH, so two measurements of the same sample could be off by 0.6 dKH and not be out of their expected uncertainty. Do not try to interpret one off measurements. Look for longer term trends.

 

[Randy Holmes-Farley Verified Community Expert]

What is your P04 at? I had a similar issue recently alk went from a stable 12 and started climbing when I posted some one told me that high phosphate can lead to the corals not taking up nutrients and and cause stuff to rise

I don't think that's either a big effect or very likely here, and cannot explain a rise without dosing. It could explain how dosing became overdosing, but pump variability can do that as well.

Some great hard corals tanks have 1+ ppm phosphate and great coral growth.

 

[MONTANTK]

Could be any or a combination of:

1. Additions that you do not recognize as adding alk
2. Declining or dosing nitrate (adds alk)
3. Slow dissolution of sand
4. Salinity changes (1.025 to 1.026 boosts alk from, say 8.0 to 8.3 dKH)
5. Test error (most kits have substntial uncertainty with each measurement

Note on the last one, even the Hanna alkalinity checker (HI772) has an uncertainty of +/-0.3 dKH, so two measurements of the same sample could be off by 0.6 dKH and not be out of their expected uncertainty. Do not try to interpret one off measurements. Look for longer term trends.

Got it, thank you for your help! Im going to test my nitrate now and depending on the outcome I should be able to rule it either testing error or drop in nitrate

 

[Mr Cypher]

I don't think that's either a big effect or very likely here, and cannot explain a rise without dosing. It could explain how dosing became overdosing, but pump variability can do that as well.

Some great hard corals tanks have 1+ ppm phosphate and great coral growth.

I can only comment to what my experience was as I dont dose at all yet and stuff started to climb lol

 

[Randy Holmes-Farley Verified Community Expert]

I can only comment to what my experience was as I dont dose at all yet and stuff started to climb lol

I understand, and all observations are useful to understand the big picture. It's just that there are so many things that happen in reef tanks that are not readily measured that to attribute any effect to one thing that is measured can be misleading.

Things like the CO2 level in the home based on open or closed windows or cooking with a gas stove, for example, can have a big impact on alk consumption, but many people never measure pH so don't necessarily make the connection.

 

[Timfish]

Hmmm okay. I don’t have any sponges or floss in the tank but I did add a filter sock that had been soaked in bleach and rinsed. Wondering if that had any impact. Other than that, I can think of anything else that would be contributing to the issue

Cryptic psonges, fungii and endoliths can all be introduced with coral colonies. What do you have growing on the backs of rocks?

 

[MONTANTK]

Cryptic psonges, fungii and endoliths can all be introduced with coral colonies. What do you have growing on the backs of rocks?

Well this is very interesting considering I just threw a bunch of sponge in my tank for my Angel to eat. Should I remove it? The Angel doesn’t pick at it anyway

 

[Randy Holmes-Farley Verified Community Expert]

Well this is very interesting considering I just threw a bunch of sponge in my tank for my Angel to eat. Should I remove it? The Angel doesn’t pick at it anyway

No, those are not a substantial source of alk or magnesium.

 

[Timfish]

Well this is very interesting considering I just threw a bunch of sponge in my tank for my Angel to eat. Should I remove it? The Angel doesn’t pick at it anyway

I'd be inclined to leave it but most sponges that grow in bright light like orange and red finger or tree sponges often available on line and at LFS will not thrive. If you see it loosing color and tissue I'd be inclined to remove it.

 

[MONTANTK]

I'd be inclined to leave it but most sponges that grow in bright light like orange and red finger or tree sponges often available on line and at LFS will not thrive. If you see it loosing color and tissue I'd be inclined to remove it.

Ah these are just black sponges, nothing special

 

[Timfish]

Ah these are just black sponges, nothing special

Chicken liver sponge? That's one I have in a lot of my tanks though they usually stay in the cryptic areas and I've always considered them beneficial. There is a black photosynthetic sponge that is invasive and will encrust over corals I'd avoid