Can low Ph (5.5-6) cause algae blooms?

[jaytech33]

Like the topic states, can a low ph level cause algae blooms?

Long post.....Sorry!

My 90 gal has been running for about 3 years now. For the past 6 months or so I have been dealing with a cloudy water issue. I tried more frequent water changes but it kept coming back, added a second canister filter (XP2), same problem. I bought a Magnum HOT and some diatom powder. Cleared up the problem if I ran once a week, but the problem was still there. Finally bought a UV sterilizer and now the problem is gone, kinda.
The water is crystal clear, but the glass keeps getting a filmy substance I use a mag float to clean. I know the UV will not kill surface algae, but before this cloudy water issue began I NEVER had to clean the glass.
Now for the ph part of the story. My tap always tests 7.2, even after 24hrs of sitting in a bucket. If I do a PWC of about 25gal the tank ph is 7. 24hrs later 6.6, another 24hrs 6.4-6.2 another 24hrs 6.0 or below.
My KH and GH are good as my 45 gal tank stays at a constant 6.8.

I gravel vac the tank and PWC 2x a week. A rena xp3 and xp2 both filled with foam pads and bioballs. Ammonia is always 0, Nitrite 0 and Nitrates no higher than 5

All the fish are fine, but I want to determine what caused this change in my tank and if I should bother to SLOWLY try to get the ph up to a stable level.

Thanks!

 

[Konigwolf]

I'd be more worried about whats causing the ph to drop after adding fresh water to the tank. The PH jumping around all the time wouldnt be great for your fish PLUS it prolly has something to do with your blooms. Nail that down then see what happens IMO

KW

 

[HarleyK]

Howdy,

cloudy water issue. I tried more frequent water changes but it kept coming back, added a second canister filter (XP2), same problem. I bought a Magnum HOT and some diatom powder. Cleared up the problem if I ran once a week, but the problem was still there. Finally bought a UV sterilizer and now the problem is gone, kinda.

Cloudy water (unless green) is often bacterial bloom. That comes from insufficient biofiltration and/or excessive bioload. The fact that a UV cleans it up supports that theory.

If I do a PWC of about 25gal the tank ph is 7. 24hrs later 6.6, another 24hrs 6.4-6.2 another 24hrs 6.0 or below.
My KH and GH are good as my 45 gal tank stays at a constant 6.8.

This also indicates that you have something rotting in your tank and/or filters. A pH drop is indicative of decomposing biomatter. Got a dead plant or rotting piece of driftwood in your tank? BTW: Please test your kH and gH before you say they're good. Your comparison to your 45 gal doesn't tell me anything.

I gravel vac the tank and PWC 2x a week. A rena xp3 and xp2 both filled with foam pads and bioballs. Ammonia is always 0, Nitrite 0 and Nitrates no higher than 5

Doesn't sound like you keep a healthy tank maintenance. You shouldn't have to gravel vac that often, or you truly put so much bioload into the tank that you have to gravel vac?! Especially bioballs are not suitable as biomedia in canister filters. There are far better materials out there, like sintered glass (Ehfi Substrat). Try switching to better biomedia, that should help. Gravel is actually a biofilter by itself, but you disturb it with every vacuuming...

What's your phosphates level, and what is your conductivity? What water treatments do you use?

HarleyK

 

[fishman61]

I use well water, pH level around 6.0 I raised it by adding crushed coral to the gravel, it raised it up to 7.0. No need to add anymore crushed coral after water changes for it raised the pH to the desired level

 

[jaytech33]

Howdy,



Cloudy water (unless green) is often bacterial bloom. That comes from insufficient biofiltration and/or excessive bioload. The fact that a UV cleans it up supports that theory.



This also indicates that you have something rotting in your tank and/or filters. A pH drop is indicative of decomposing biomatter. Got a dead plant or rotting piece of driftwood in your tank? BTW: Please test your kH and gH before you say they're good. Your comparison to your 45 gal doesn't tell me anything.




Doesn't sound like you keep a healthy tank maintenance. You shouldn't have to gravel vac that often, or you truly put so much bioload into the tank that you have to gravel vac?! Especially bioballs are not suitable as biomedia in canister filters. There are far better materials out there, like sintered glass (Ehfi Substrat). Try switching to better biomedia, that should help. Gravel is actually a biofilter by itself, but you disturb it with every vacuuming...



What's your phosphates level, and what is your conductivity? What water treatments do you use?


HarleyK

All fake plants and driftwood. Just did some tests: Tap water KH is 4, GH is 6. Tank water (72hrs since PWC) KH is 1, GH is 9.

I do have rena ceramic rings mixed in with the bioballs. As far as bioload, my current stock is below in my signature.
Before the cloudy water problem I did not do a gravel vac every time. I started after the problem started to try and fix the problem.

Sorry no phosphates kit, and I am not sure how to test conductivity.
I use Prime with every PWC.

Thanks

 

[cchhcc]

Great post HarleyK! Pretty much covered it all!

 

[HarleyK]

Howdy,

All fake plants and driftwood.

If it's real driftwood, then remove it - that might solve your problem in two ways - driftwood can lower hardness and pH naturally, and rotting wood will lower pH via different pathway.

Just did some tests: Tap water KH is 4, GH is 6. Tank water (72hrs since PWC) KH is 1, GH is 9.

Your water is fairly soft. Try adding marble chips to your canister filters, or age water in a barrel with marble chips (or crushed coral) until you are able to determine the cause of the drop.

HarleyK

 

[jaytech33]

Howdy,



If it's real driftwood, then remove it - that might solve your problem in two ways - driftwood can lower hardness and pH naturally, and rotting wood will lower pH via different pathway.



Your water is fairly soft. Try adding marble chips to your canister filters, or age water in a barrel with marble chips (or crushed coral) until you are able to determine the cause of the drop.

HarleyK

Thanks Harley. The driftwood is fake also. I will add some crushed coral in the filters to stabilize the ph.

All decor in the tank has been the same since day one. Nothing added to the tank that could cause the issue.

Looking back through my notes, the ph drop and the cloudy water problem started about the same time. Give or take a week.


​

 

[HarleyK]

Howdy,

Looking back through my notes, the ph drop and the cloudy water problem started about the same time. Give or take a week.

First off, my respect for keeping a log. That's great. I do the same.

Second, your stocking level is not very high for 90 gal. That's good. Did you change the food source for your fish, did the water cloudiness coincide with a filter cleaning or water change? How deep do you gravel-vac? Maybe it's time to go all the way to the bottom and underneath decor. I know I said earlier that it's part of the biofilter, but if there's anything rotting in your substrate it needs to get out.

HarleyK

 

[jaytech33]

Howdy,



First off, my respect for keeping a log. That's great. I do the same.

Second, your stocking level is not very high for 90 gal. That's good. Did you change the food source for your fish, did the water cloudiness coincide with a filter cleaning or water change? How deep do you gravel-vac? Maybe it's time to go all the way to the bottom and underneath decor. I know I said earlier that it's part of the biofilter, but if there's anything rotting in your substrate it needs to get out.

HarleyK

I am very thorough about keeping my tanks clean, water changes, etc.

It puzzles me why its only the one tank. The other tank though a 45 gal and stocked with 5 tiger barbs and 1 iridescent shark is perfect. Both tanks use the same tap water, prime during water changes and I use the same food in both tanks.

I feed tetra tropical flakes, OSI shrimp pellets and Hikari algae wafers.

When I gravel vac I go down to the bottom, get out all the brown "gunk"
4 times a year I pull the decor to do a complete gravel clean.

I was told when this first started that I am cleaning my canisters too often. Back before this happened I was cleaning the XP3 every month, but I only changed the polish pad at the top. The biomedia was never cleaned, and the bottom sponges were only rinsed in the tank water left in the canister.
So with that being said I added the xp2 to the tank and have not cleaned either since the first week of January. Since the water output is good and my nitrates are low I guess I can do a filter cleaning every 6 months, not every 1 month.

So what caused the cloudy water, this "slime" on the glass, and low Ph after 2+ years is a mystery to me. The only change is that the fish grew!

The only thing I can think of at this point is a change in my tap water. I will admit I was not checking Kh and Gh until the problem started.

Thanks