Would a co2 scrubber correct that though?
Yes.
This is why I recommended an air stone. It would be a cheap way to find out if the air in your house would support a higher pH or if something like an outside airline or CO2 scrubber would be necessary.
I'll try to give you the over simplified version of Alk and pH. Poor Randy will probably cringe when he reads this.
Alkalinity is a combination of Carbonate (CO3) and Bi-Carbonate (HCO3). The ratio of these changes based on pH. As pH drops, the Carbonate is converted to Bi-Carbonate. Coral "tend" to prefer carbonate to grow which is why we like a higher pH. Carbonate and Bi-Bicarbonate together are what we measure as Total Alkalinity.
pH is a measure of the hydrogen ions in the water. Carbon Dioxide (CO2) in water (H2O) creates Carbonic Acid (H2CO3). The hydrogen ions in an acid are what lowers pH. So, the more CO2 in the water, the more Carbonic Acid you get, and the more pH goes down.
Carbonate, Bi-Carbonate and Carbonic Acid all exist in a balance in an aquarium CO3 <--> HCO3 <--> H2CO3. If you add Carbonate, it shifts the equation to the left and pH goes up (Total Alk goes up too). If you add CO2, the equation shifts right and pH goes down (Total Alk does not change). So, if our Alk is where we want it, but pH is low, our best method to correct it is to reduce Carbonic Acid, which we do by reducing CO2.
Fish, along with decaying plants, fish food, and some bacteria release CO2. Most algaes consume CO2. To complicate this, we also have gas exchange with the air. These are the 3 main factors that determine the CO2 level in your aquarium. If you add aeration you increase the impact that the gas exchange has in relation to the other 2 factors. So, if the dissolved gas in your aquarium has more CO2 than the air you start mixing it with, your dissolved CO2 will go down and your pH will go up. If your aquarium has less CO2 than the air you start mixing it with, your dissolved CO2 will go up and your pH will go down. If you aerate your tank with outside air (350ppm), pH will track almost exactly with Total Alkalinity.
