Phosphates, Alkalinity, and Calcium... oh my!

[JSully_94]

Hello Everyone,

I have a few questions regarding the water chemistry of my aquarium that I hope you all will answer. I currently use Hanna Instruments colorimeters to test for phosphates, alkalinity, and calcium. My questions/concerns are as followed:

1. My phosphates now read 0.00, utilizing Hanna's ULR colorimeter. Over the past months (since January), they have been hovering around .01 - .03. I utilize PhosGuard to keep phosphates down as I have experienced severe green hair algae outbreaks in the past (in another tank) and I do not want to deal with that again. My question is, since my phosphates have now bottomed out, will I see any noticeable differences in my corals' health/growth? I've read 0 phosphates translates to 0 "nutrients," and that is bad for corals. Thoughts?

2. I've been having issues with low alkalinity. For some reason, the alkalinity in my current tank stays below 7 for the most part. On average, it registers at 6.783333... I've started dosing Seachem's Reef-Buffer once a week when I do my water changes as my pH has been historically low as well. Now, my pH usually hovers around 8.0-8.1, but my alkalinity still drops. Does anyone have any advice on how to remedy this? Will continuous fluctuations in alkalinity spell havoc for my corals or any other inhabitants within my aquarium?

Overall, my magnesium and calcium are pretty constant.

A brief snapshot of my aquarium,
IM Nuvo fusion 20 gallon
Salt mix: reef cyrstals
Inhabitants: Two clownfish, one lawnmower blenny, two hermit crabs, one gsp, one torch, one nepthea, one birdsnest, one candy cane, one pocillopora, one green psammacora, and one chalice echinopora coral.

Any and all advice is welcomed and appreciated.

Thanks

 

[Randy Holmes-Farley Verified Community Expert]

The phosphate should be higher. Remove the phosguard.

Use More alk supplement, such as baking soda or the Seachem product.

Forget the pH for now. It is fine.

 

[JSully_94]

The phosphate should be higher. Remove the phosguard.

Use More alk supplement, such as baking soda or the Seachem product.

Forget the pH for now. It is fine.

So having 0 phosphates is bad?

 

[Copingwithpods]

I'd stop the pH buffer all together as they are short live and you'll be dosing that all day and night with no improvements, in fact forget pH all together instead dose a 2 part solution. As your pH is 7 your water is basically neutral. You can get this back in line with a few water changes. Your alk and cal consumption will dictate if water changes alone will be enough to keep up or if a dedicated 2 part regiment will be necessary.

 

[The cats wrasse]

You running a skimmer? Also if your looking to up your nutrients just dose phyto

 

[dadnjesse]

I keep my Alkalinity around 7. As long as it's consistent you'll be fine.

 

[lapin]

+1 above @Copingwithpods
Water changes are a good thing
A bit of P04 is needed.

 

[JSully_94]

You running a skimmer? Also if your looking to up your nutrients just dose phyto

I'm running a reef octopus classic 90 HOB. It's for sure overkill, but it works well. Should I be increasing my nutrients? That's my question. How does one measure "nutrients"? Can you have nutrients but have 0 phosphates?

 

[JSully_94]

+1 above @Copingwithpods
Water changes are a good thing
A bit of P04 is needed.

I do a 15% water change weekly (3 gallons), but my alkalinity is still low. I'm assuming too much carbon in the room, but I'm interested in what you all think.

 

[lapin]

You need P04 for things to grow in reef tank.

Redfield ratio - Wikipedia

en.wikipedia.org

Reef Crystals is very high in Alk. You might try bigger water changes to see if that makes a difference.

 

[ScottB]

So having 0 phosphates is bad?

Yes to be blunt. Deadly for corals when it comes to that.

 

[JSully_94]

You need P04 for things to grow in reef tank.

Yes to be blunt. Deadly for corals when it comes to that.

So how does one go about increasing P04 without going overboard and potentially causing an algae outbreak?

 

[The cats wrasse]

So having 0 phosphates is bad?

The only thing you really want at 0 should be amonia

I'm running a reef octopus classic 90 HOB. It's for sure overkill, but it works well. Should I be increasing my nutrients? That's my question. How does one measure "nutrients"? Can you have nutrients but have 0 phosphates?

Yeah the inhabitants of your tank will consume nutrients ...its like alot of people test for p04 trying to see why they have algae growth but the tester reads 0 ....b.c the algae is absorbing it ....now I'm not an sps person but know hoe temperamental they are but in all my tanks I never run tests I use algae scrubbers to make sure I'm growing algae and just check my corals polyps if they are reaching for the stars and im growing algae well I chek my salinity and keep her moving

 

[Spitty]

Turn off your skimmer or just run it at night, feed more, keep testing

 

[Crustaceon]

I have to agree with many here. With a twenty gallon tank, I’d be more inclined to just do something like a 10-15% water change weekly. Mix three gallons the night before, check salinity, put an airstone in the bucket to aerate overnight and the next day, add a heater to match the temperature. Suck three gallons out into a matching bucket next to the freshly mixed saltwater while you’re siphoning the sand. Add the good water back into the tank and voila, you’re done. You shouldn’t need any phosphate removal media or buffers as long as you aren’t overfeeding your tank’s inhabitants and stay consistent with your water change routine. As you add more corals to your tank, weekly water changes might not keep up with alk/cal/mg demand and then you’ll have to decide on dosing with something like Kalkwasser in your ato or 2-part dosing. Both are great options but only when that time comes. I don’t think that time has come yet. For now, do your water changes, including siphoning your sandbed and check alk/cal/mag. Don’t stress over nitrates and phosphates. It’s really hard to have issues with those parameters if you stay on top of your water changes and don’t overfeed. Do your maintenance and they’ll stay naturally low, but not too low, which is where pretty much every reefer wants them.

 

[The cats wrasse]

I highly recomend algae scrubbers if your fear is algae growing in the display

 

[Randy Holmes-Farley Verified Community Expert]

So having 0 phosphates is bad?

yes. Bad for corals and risks dinos.

 

[Crustaceon]

So having 0 phosphates is bad?

It’s worse than having high phosphates in pretty much all scenarios I can think of. I’d rather have 1ppm phosphates than zero any day and that’s with acropora.